Change the logs protocol to incldue the span_id (#15355)

Author: cleptric

develop-docs/sdk/telemetry/logs.mdx

@@ -40,6 +40,7 @@ The `log` envelope item payload is a JSON object that represents a Sentry Log.
 {
   "timestamp": 1544719860.0,
   "trace_id": "5b8efff798038103d269b633813fc60c",
+  "span_id": "b0e6f15b45c36b12",
   "level": "info",
   "body": "User John has logged in!",
   "attributes": {
@@ -58,10 +59,6 @@ The `log` envelope item payload is a JSON object that represents a Sentry Log.
     "sentry.release": {
       "value": "1.0.0",
       "type": "string"
-    },
-    "sentry.trace.parent_span_id": {
-      "value": "b0e6f15b45c36b12",
-      "type": "string"
     }
   }
 }
@@ -77,6 +74,10 @@ It consists of the following fields:
 
 : **String, required**. The trace id of the log. The value should be 16 random bytes encoded as a hex string (32 characters long). The trace id should be grabbed from the current propagation context in the SDK.
 
+`span_id`
+
+: **String, optional**. The span id of the span that was active when the log was collected. The value should be 8 random bytes encoded as a hex string (16 characters long). The span id should be grabbed from the current active span in the SDK.
+
 `level`
 
 : **String, required**. The severity level of the log. One of `trace`, `debug`, `info`, `warn`, `error`, `fatal` (in order of lowest to highest).
@@ -274,16 +275,14 @@ By default the SDK should attach the following attributes to a log:
 
 1. `sentry.environment`: The environment set in the SDK if defined.
 2. `sentry.release`: The release set in the SDK if defined.
-3. `sentry.trace.parent_span_id`: The span id of the span that was active when the log was collected. This should not be set if there was no active span.
-4. `sentry.sdk.name`: The name of the SDK that sent the log
-5. `sentry.sdk.version`: The version of the SDK that sent the log
-6. `sentry.replay_id`: The replay id of the replay that was active when the log was collected. This should not be set if there was no active replay.
+3. `sentry.sdk.name`: The name of the SDK that sent the log
+4. `sentry.sdk.version`: The version of the SDK that sent the log
+5. `sentry.replay_id`: The replay id of the replay that was active when the log was collected. This should not be set if there was no active replay.
 
 ```json
 {
   "sentry.environment": "production",
   "sentry.release": "1.0.0",
-  "sentry.trace.parent_span_id": "b0e6f15b45c36b12",
   "sentry.sdk.name": "sentry.javascript.node",
   "sentry.sdk.version": "9.11.0",
   "sentry.replay_id": "36b75d9fa11f45459412a96c41bdf691"
@@ -411,7 +410,7 @@ If SDK authors feel the need, they can also introduce additional options to beyo
 
 #### Tracing
 
-Logs should be associated with traces if possible. If a log is recorded during an active span, the SDK should set the `sentry.trace.parent_span_id` attribute to the span id of the span that was active when the log was collected.
+Logs should be associated with traces if possible. If a log is recorded during an active span, the SDK should set the `span_id` property of the log to the span id of the span that was active when the log was collected.
 
 #### Replays