upflit(beta): fix: avatar image uri (#10500)

[wmontwe]

Uplift #10500 to beta

[thunderbird-botmobile]

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[Approval Request]
Original Issue/Pull request: #10477
Regression caused by (issue #): #10210
User impact if declined: User could change their avatar image, but the update won't propagate
Testing completed (on daily, beta, etc.): daily, debug
Introduces or modifies localizable strings (yes/no): no
Skips a database migration (yes/no): no
Risk to taking this patch (and alternatives if risky): Low as it's ensuring a versioned URI is used to signal change of the avatar image.