Fix retries: don't upload metadata three times

app/src/main/java/com/stevesoltys/seedvault/worker/ApkBackupManager.kt

@@ -135,6 +135,7 @@ internal class ApkBackupManager(
         for (i in 1..n) {
             try {
                 block()
+                return
             } catch (e: Exception) {
                 if (i == n) throw e
                 Log.e(TAG, "Error (#$i), we'll keep trying", e)

app/src/test/java/com/stevesoltys/seedvault/worker/ApkBackupManagerTest.kt

@@ -234,6 +234,10 @@ internal class ApkBackupManagerTest : TransportTest() {
             apkBackup.backupApkIfNecessary(notAllowedPackages[1], any())
             metadataOutputStream.close()
         }
+        // metadata should only get uploaded once
+        verify(exactly = 1) {
+            metadataManager.uploadMetadata(metadataOutputStream)
+        }
     }
 
     @Test