fix: Do not upload/read files when path starts with gs:// (#2075)

Fixes #1971 

When user provides `gs://` path in `other-files` we should not upload it again.
```
Files.readAllBytes(Paths.get(file))
```
will never succeed when the path starts with `gs://` 

## Test Plan
> How do we know the code works?

1. [flank test bucket](https://console.cloud.google.com/storage/browser/flank-open-source.appspot.com/test?project=flank-open-source&pageState=(%22StorageObjectListTable%22:(%22f%22:%22%255B%255D%22))&prefix=&forceOnObjectsSortingFiltering=false)
1. run `./gradlew flankFullRun`
1. prepare config with:
    ```
    other-files:
        /sdcard/[some file name]: gs://[path to file uploaded to the bucket, you can reuse existing one]
    ```
1. run tests
1. go to result bucket and check if there is a file from config under `/artifacts/sdcard/` path

test_runner/src/main/kotlin/ftl/run/platform/android/UploadOtherFiles.kt

@@ -4,6 +4,7 @@ import ftl.api.RemoteStorage
 import ftl.api.uploadToRemoteStorage
 import ftl.args.AndroidArgs
 import ftl.args.IArgs
+import ftl.config.FtlConstants.GCS_PREFIX
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.async
 import kotlinx.coroutines.awaitAll
@@ -24,9 +25,9 @@ internal suspend fun AndroidArgs.uploadObbFiles(): Map<String, String> = corouti
     }.awaitAll().toMap()
 }
 
-fun upload(file: String, rootGcsBucket: String, runGcsPath: String): String {
-    return uploadToRemoteStorage(
+fun upload(file: String, rootGcsBucket: String, runGcsPath: String): String =
+    if (file.startsWith(GCS_PREFIX)) file
+    else uploadToRemoteStorage(
         RemoteStorage.Dir(rootGcsBucket, runGcsPath),
         RemoteStorage.Data(file, Files.readAllBytes(Paths.get(file)))
     )
-}