DocumentsStorageProviderIT: add timeout to testServerChangedFileContent()

This test sometimes hangs forever, resulting in (for example) CI builds being killed.
This way, only this test fails and the rest of the suite continues.

Signed-off-by: Álvaro Brey Vilas <alvaro.brey@nextcloud.com>

src/androidTest/java/com/owncloud/android/providers/DocumentsStorageProviderIT.kt

@@ -176,7 +176,8 @@ class DocumentsStorageProviderIT : AbstractOnServerIT() {
         assertExistsOnServer(client, ocFile1.remotePath, false)
     }
 
-    @Test
+    @Suppress("MagicNumber")
+    @Test(timeout = 5 * 60 * 1000)
     fun testServerChangedFileContent() {
         // create random file
         val file1 = rootDir.createFile("text/plain", RandomString.make())!!