fix: Validate chat button url only when chatUrl is set

[rouke-broersma]

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Fixes #12655

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (0f500a5) 47.79% compared to head (22187f7) 47.79%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #12749   +/-   ##
=======================================
  Coverage   47.79%   47.79%           
=======================================
  Files         246      246           
  Lines       41968    41968           
=======================================
  Hits        20058    20058           
  Misses      19910    19910           
  Partials     2000     2000           

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[crenshaw-dev]

/cherry-pick release-2.6

[crenshaw-dev]

/cherry-pick release-2.5

[crenshaw-dev]

/cherry-pick release-2.4