acc: ensure Delay does not prevent shutdown (#3548)

For tests that set Delay, do not sleep but exit earlier if context is
cancelled (means server is shutting down).

Before this change:

```
        --- PASS: TestAccept/telemetry/timeout/DATABRICKS_CLI_DEPLOYMENT=terraform (5.53s)
        --- PASS: TestAccept/telemetry/timeout/DATABRICKS_CLI_DEPLOYMENT=direct-exp (5.53s)

```
After this change:

```
        --- PASS: TestAccept/telemetry/timeout/DATABRICKS_CLI_DEPLOYMENT=terraform (0.63s)
        --- PASS: TestAccept/telemetry/timeout/DATABRICKS_CLI_DEPLOYMENT=direct-exp (0.63s)
```

Author: denik

acceptance/internal/prepare_server.go

@@ -168,7 +168,23 @@ func startLocalServer(t *testing.T,
 		items := strings.Split(stub.Pattern, " ")
 		require.Len(t, items, 2)
 		s.Handle(items[0], items[1], func(req testserver.Request) any {
-			time.Sleep(stub.Delay)
+			if stub.Delay > 0 {
+				ctx := req.Context
+
+				timer := time.NewTimer(stub.Delay)
+				defer timer.Stop()
+
+				select {
+				case <-timer.C:
+					break
+				case <-ctx.Done():
+					// Client canceled/connection closed; just exit.
+					// Optional: log the reason (context deadline, cancellation, etc.)
+					t.Logf("request canceled: %v", ctx.Err())
+					return nil
+				}
+			}
+
 			return stub.Response
 		})
 	}

libs/testserver/server.go

@@ -2,6 +2,7 @@ package testserver
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -37,6 +38,7 @@ type Request struct {
 	Body      []byte
 	Vars      map[string]string
 	Workspace *FakeWorkspace
+	Context   context.Context
 }
 
 type Response struct {
@@ -64,6 +66,7 @@ func NewRequest(t testutil.TestingT, r *http.Request, fakeWorkspace *FakeWorkspa
 		Body:      body,
 		Vars:      mux.Vars(r),
 		Workspace: fakeWorkspace,
+		Context:   r.Context(),
 	}
 }
 
@@ -271,6 +274,9 @@ func (s *Server) Handle(method, path string, handler HandlerFunc) {
 			}
 		} else {
 			respAny := handler(request)
+			if respAny == nil && request.Context.Err() != nil {
+				return
+			}
 			resp = normalizeResponse(s.t, respAny)
 		}