fixup! Tor Browser localization migration scripts.

TB 43531: Convert bridge dialog button strings to use "label" attribute.

tools/torbrowser/l10n/migrations/bug-43531-bridge-dialog-buttons.py

+from fluent.migrate.helpers import transforms_from
+
+
+def migrate(ctx):
+    # Convert
+    #
+    # my-button = MY TEXT
+    #
+    # to
+    #
+    # my-button2 =
+    #   .label = MY TEXT
+    ctx.add_transforms(
+        "tor-browser.ftl",
+        "tor-browser.ftl",
+        transforms_from(
+            """
+bridge-dialog-button-connect2 =
+    .label = { COPY_PATTERN(path, "bridge-dialog-button-connect") }
+bridge-dialog-button-accept2 =
+    .label = { COPY_PATTERN(path, "bridge-dialog-button-accept") }
+bridge-dialog-button-submit2 =
+    .label = { COPY_PATTERN(path, "bridge-dialog-button-submit") }
+""",
+            path="tor-browser.ftl",
+        ),
+    )