Fix manifest code snippet tag (#5069)

Author: marandaneto

src/platforms/android/common/performance/instrumentation/automatic-instrumentation.mdx

@@ -23,19 +23,19 @@ The transaction starts before each Activity's `onCreate` method is called.
 _The Activity's instrumentation is enabled by default, but you may disable it by setting:_
 
 ```xml {filename:AndroidManifest.xml}
-<manifest>
+<application>
     <meta-data android:name="io.sentry.traces.activity.enable" android:value="false" />
-</manifest>
+</application>
 ```
 
 The transaction finishes after each Activity's `onResume` method is executed.
 
 _The transaction finishes automatically, but you may disable it by setting:_
 
 ```xml {filename:AndroidManifest.xml}
-<manifest>
+<application>
     <meta-data android:name="io.sentry.traces.activity.auto-finish.enable" android:value="false" />
-</manifest>
+</application>
 ```
 
 We offer the possibility to finish the transaction manually. For example, you might want to finish the transaction after an API call triggered on Activity's `onCreate` and shown the data to the user. To achieve that you can do:
@@ -143,9 +143,9 @@ The app start is only measured if the process is of the importance [RunningAppPr
 You can opt out of Android's Activity Instrumentation and App Start Instrumentation using options:
 
 ```xml {filename:AndroidManifest.xml}
-<manifest>
+<application>
     <meta-data android:name="io.sentry.traces.activity.enable" android:value="false" />
-</manifest>
+</application>
 ```
 
 Cold and warm start are Mobile Vitals, which you can learn about in the [full documentation](/product/performance/mobile-vitals).
@@ -239,9 +239,9 @@ If the view doesn't have the `id` assigned, the transaction won't be captured be
 The UI instrumentation is disabled by default, but you can enable it by setting:
 
 ```xml {filename:AndroidManifest.xml}
-<manifest>
+<application>
     <meta-data android:name="io.sentry.traces.user-interaction.enable" android:value="true" />
-</manifest>
+</application>
 ```
 
 The transaction finishes automatically after it reaches the specified [idleTimeout](/platforms/android/configuration/options/#idle-timeout) and all of its child spans are finished. The `idleTimeoout` defaults to `3000` milliseconds (three seconds). You can also disable the idle timeout by setting it to `null`, but the transaction must be finished manually in this case.