IDEA-327274 Revert "IDEA-338005 call indicator.start after the progress indicator is shown"

This reverts commit d2576dd2d846daa0b022e91991660fee85f03280.

Consider this piece:
```
withContext(Dispatchers.EDT) {
  showIndicatorInUI(project, taskInfo, indicator)
}
```

`showIndicatorInUI` was completed but `withContext` resumed with `CancellationException` if the coroutine is cancelled
concurrently, which happens if the task takes about 300ms and completes while `showIndicatorInUI` is executed.
`CancellationException` from `withContext` prevented `indicator.finish`.

`withContext` resuming with CE even if block completed without CE is tracked here:
Kotlin/kotlinx.coroutines#3504

GitOrigin-RevId: e684335dcb7bb2eb8abb7399eec7cdf1788470d2

Author: dovchinnikov

platform/platform-impl/src/com/intellij/openapi/progress/impl/PlatformTaskSupport.kt

@@ -188,19 +188,19 @@ private fun CoroutineScope.showIndicator(
     delay(DEFAULT_PROGRESS_DIALOG_POSTPONE_TIME_MILLIS.toLong())
     tracer.spanBuilder("Progress: ${taskInfo.title}").startSpan().use {
       val indicator = coroutineCancellingIndicator(taskJob) // cancel taskJob from UI
-      val indicatorAdded = withContext(Dispatchers.EDT) {
-        showIndicatorInUI(project, taskInfo, indicator)
-      }
-      if (indicatorAdded) {
-        indicator.start()
-        try {
-          indicator.updateFromFlow(stateFlow)
+      indicator.start()
+      try {
+        val indicatorAdded = withContext(Dispatchers.EDT) {
+          showIndicatorInUI(project, taskInfo, indicator)
         }
-        finally {
-          indicator.stop()
-          indicator.finish(taskInfo)
+        if (indicatorAdded) {
+          indicator.updateFromFlow(stateFlow)
         }
       }
+      finally {
+        indicator.stop()
+        indicator.finish(taskInfo)
+      }
     }
   }
 }