integrations-url-modal: Add URL parameter for filtering by branches.

Use the config option "branches" to enable the UI for filtering
branches.

Fixes: #33736.

tools/lib/capitalization.py

@@ -180,6 +180,8 @@ IGNORED_PHRASES = [
     r"weeks",
     # Used in "Who can subscribe to this channel" label.
     r"everyone except guests can subscribe to any public channel",
+    # Used in branch-filtering label in the integration-url-modal.
+    r"comma-separated list",
 ]
 
 # Sort regexes in descending order of their lengths. As a result, the