Adding SDKLogger Override in Example App

[mliao95]

Issue Number:

Description:

What are the changes? Why are we making them?

This PR enhances the SDK Logger example workflows in the example application. The SDK Logger example now includes overriding the SDKLogger with a custom logger that will output a log file when using the app.

There is also some import cleanup in the SDK's ChatSession.kt file.

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Functional backward compatibility:

Does this change introduce backwards incompatible changes? [YES/NO]

NO

Does this change introduce any new dependency? [YES/NO]

NO

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Testing:

Is the code unit tested?

YES

Have you tested the changes with a sample UI (e.g. Android Mobile Chat Example)?

YES

Here are a list of manual test cases to run through:

• Initiating chat and connecting with an agent
• Retrieving transcript
• Disconnecting from chat
• Sending a message to the agent
  • See typing bubbles on agent side
  • See read/delivered receipt on client side
  • Receiving a message from the agent
  • See typing bubbles on client side
  • See read/delivered receipt on agent side
  • Sending an attachment to the agent (try .txt, .pdf, .jpg)
  • Preview the attachment on click
  • Receiving an attachment from the agent
  • Preview the attachment on click
• Close the application (Without ending chat) → open app again → Start chat → Should Retrieve transcript from a previous chat session