[BUG] Microservices with no local source bundles should be able to use "latest" source messages from VIP service

Describe the bug
Microservices with no local source bundles should be able to use "latest" source messages from VIP service for

1. fallback when requested locale is not supported
2. for when new messages are added/updated in "messages_latest.json" but not yet added/updated in messages_.json.
   The bug is that TranslationMessage.getMessage is not able to retrieve the "latest" messages and use it as source.

To Reproduce
See new test case TranslationMessageTest.testGetMessageNoLocalSource
Prepare the client app in such a way that offline mode is disabled, no local source bundle is available.
In VIP service, make sure messages_latest.json and messages_en.json exists.

1. Add a new message in messages_latest.json
2. Call TranslationMessage.getMessage(en, component, key) for the newly added message in step 1.
3. Notice that an exception will be thrown.

AND/OR

1. Update an existing message in messages_latest.json
2. Call TranslationMessage.getMessage(en, component, key) for the updated message in step 1.
3. Notice that the older value that is in messages_en.json will be returned.

Expected behavior
TranslationMessage.getMessage should return whatever is in messages_latest.json in VIP service.