Fix live photo identification

[OldBuddy]

Description

• fix: invalid content_type property identification for a live photo message.
• refactor: convert if blocks to match statement on content_type property.

Fixes #1841

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[github-actions]

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