Mob 3730 file preview doesnt work in chat for messages with attachments

[DavDo]

Jira issue:
https://glia.atlassian.net/browse/MOB-3730

Important

Sorry for the big PR, I tried to split it into smaller commits 1 - rename, 2 - refactoring, 3 - unit tests(currently working on), but refactoring still is bigger than expected, but sometimes it is the only way to do refactorings.

What was solved?

• I renamed FileAttachment LocalAttachment to distinguish clearly between local and remote attachments
• I removed SendMessagePayload local wrapper since we can get all the information from core sdks SendMessagePayload
• I made changes to the Chat logic to use local attachments with Uri for visitor-sent attachments instead of downloading and caching them locally
• I removed the Unsent message type because currently, we're adding all the visitor messages as a preview and then updating their status in chat

To align chat behavior with iOS

• Now tapping on the image preview or attachment view will always open the image preview or attachment view page, even in case of an error.
• In case of an error, a visitor now has to click the message row or attachment container(not preview) to resend the message.

I will also add a video later to demonstrate these changes.

Release notes:

• Feature
• Ignore
• Release notes (Is it clear from the description here?)
• Migration guide (If changes are needed for integrator already using the SDK - what needs to be communicated? Add underneath please)

Additional info:

• Is the feature sufficiently tested? All tests fixed? Necessary unit, acceptance, snapshots added? Check that at least new public classes & methods are covered with unit tests
• Did you add logging beneficial for troubleshooting of customer issues?
• Did you add new logging? We would like the logging between platforms to be similar. Refer to Logging from Android SDKs → Things to consider for newly added logs in Confluence for more information.

Screenshots: