fix: Fixing missing OpenTelemetry::Context detach on Excon instrumentation

When a span is not recorded, for example when you are sampling traces,
the OpenTelemetry::Context attached on `request_call` is never detached.
This happens because `handle_response` is doing nothing if
`span.recording?` is false.

Here is example of the error that the missing detach generated:
```
ERROR -- : OpenTelemetry error: calls to detach should match corresponding calls to attach.
```

Author: pafuent

instrumentation/excon/lib/opentelemetry/instrumentation/excon/middlewares/dup/tracer_middleware.rb

@@ -84,6 +84,7 @@ def self.around_default_stack
 
             def handle_response(datum)
               datum.delete(:otel_span)&.tap do |span|
+                OpenTelemetry::Context.detach(datum.delete(:otel_token)) if datum.include?(:otel_token)
                 return unless span.recording?
 
                 if datum.key?(:response)
@@ -99,7 +100,6 @@ def handle_response(datum)
                 end
 
                 span.finish
-                OpenTelemetry::Context.detach(datum.delete(:otel_token)) if datum.include?(:otel_token)
               end
             rescue StandardError => e
               OpenTelemetry.handle_error(e)

instrumentation/excon/lib/opentelemetry/instrumentation/excon/middlewares/old/tracer_middleware.rb

@@ -76,6 +76,7 @@ def self.around_default_stack
 
             def handle_response(datum)
               datum.delete(:otel_span)&.tap do |span|
+                OpenTelemetry::Context.detach(datum.delete(:otel_token)) if datum.include?(:otel_token)
                 return unless span.recording?
 
                 if datum.key?(:response)
@@ -90,7 +91,6 @@ def handle_response(datum)
                 end
 
                 span.finish
-                OpenTelemetry::Context.detach(datum.delete(:otel_token)) if datum.include?(:otel_token)
               end
             rescue StandardError => e
               OpenTelemetry.handle_error(e)

instrumentation/excon/lib/opentelemetry/instrumentation/excon/middlewares/stable/tracer_middleware.rb

@@ -76,6 +76,7 @@ def self.around_default_stack
 
             def handle_response(datum)
               datum.delete(:otel_span)&.tap do |span|
+                OpenTelemetry::Context.detach(datum.delete(:otel_token)) if datum.include?(:otel_token)
                 return unless span.recording?
 
                 if datum.key?(:response)
@@ -90,7 +91,6 @@ def handle_response(datum)
                 end
 
                 span.finish
-                OpenTelemetry::Context.detach(datum.delete(:otel_token)) if datum.include?(:otel_token)
               end
             rescue StandardError => e
               OpenTelemetry.handle_error(e)

instrumentation/excon/test/opentelemetry/instrumentation/excon/dup/instrumentation_test.rb

@@ -199,6 +199,26 @@
 
       _(span.attributes['peer.service']).must_equal 'example:custom'
     end
+
+    describe 'context detachment with non-recording spans' do
+      before do
+        @original_sampler = OpenTelemetry.tracer_provider.sampler
+        OpenTelemetry.tracer_provider.sampler = OpenTelemetry::SDK::Trace::Samplers::ALWAYS_OFF
+      end
+
+      after do
+        OpenTelemetry.tracer_provider.sampler = @original_sampler
+      end
+
+      it 'detaches context when span is not recorded' do
+        initial_context = OpenTelemetry::Context.current
+        Excon.get('http://example.com/success')
+        final_context = OpenTelemetry::Context.current
+
+        _(final_context).must_equal initial_context
+        _(exporter.finished_spans).must_be_empty
+      end
+    end
   end
 
   describe 'untraced?' do

instrumentation/excon/test/opentelemetry/instrumentation/excon/old/instrumentation_test.rb

@@ -158,6 +158,26 @@
 
       _(span.attributes['peer.service']).must_equal 'example:custom'
     end
+
+    describe 'context detachment with non-recording spans' do
+      before do
+        @original_sampler = OpenTelemetry.tracer_provider.sampler
+        OpenTelemetry.tracer_provider.sampler = OpenTelemetry::SDK::Trace::Samplers::ALWAYS_OFF
+      end
+
+      after do
+        OpenTelemetry.tracer_provider.sampler = @original_sampler
+      end
+
+      it 'detaches context when span is not recorded' do
+        initial_context = OpenTelemetry::Context.current
+        Excon.get('http://example.com/success')
+        final_context = OpenTelemetry::Context.current
+
+        _(final_context).must_equal initial_context
+        _(exporter.finished_spans).must_be_empty
+      end
+    end
   end
 
   describe 'untraced?' do

instrumentation/excon/test/opentelemetry/instrumentation/excon/stable/instrumentation_test.rb

@@ -172,6 +172,26 @@
 
       _(span.attributes['peer.service']).must_equal 'example:custom'
     end
+
+    describe 'context detachment with non-recording spans' do
+      before do
+        @original_sampler = OpenTelemetry.tracer_provider.sampler
+        OpenTelemetry.tracer_provider.sampler = OpenTelemetry::SDK::Trace::Samplers::ALWAYS_OFF
+      end
+
+      after do
+        OpenTelemetry.tracer_provider.sampler = @original_sampler
+      end
+
+      it 'detaches context when span is not recorded' do
+        initial_context = OpenTelemetry::Context.current
+        Excon.get('http://example.com/success')
+        final_context = OpenTelemetry::Context.current
+
+        _(final_context).must_equal initial_context
+        _(exporter.finished_spans).must_be_empty
+      end
+    end
   end
 
   describe 'untraced?' do