Adding Fix for flakey test caused while buildng bicep template (#7345)

# Description

Added changes to sequentialy copy the stdout to buffer instead of
copying it asynchronously.

## Type of change

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Fixes: #7194

Signed-off-by: Vishwanath Hiremath <[email protected]>

pkg/cli/bicep/build.go

@@ -59,12 +59,10 @@ func runBicepRaw(args ...string) ([]byte, error) {
 		return nil, fmt.Errorf("failed executing %q: %w", fullCmd, err)
 	}
 
-	// asynchronously copy to our buffer, we don't really need to observe
+	// copy to our buffer, we don't really need to observe
 	// errors here since it's copying into memory
 	buf := bytes.Buffer{}
-	go func() {
-		_, _ = io.Copy(&buf, stdout)
-	}()
+	_, _ = io.Copy(&buf, stdout)
 
 	// Wait() will wait for us to finish draining stderr before returning the exit code
 	err = c.Wait()