fix(collections): one confirmed Clear recently viewed action (#1865)

A playlist's own recently viewed page (/workspace/<provider>/<id>/recent,
opened from the dashboard's recently viewed rails) showed two clear buttons:
the page's "Clear recently viewed <type>", which confirms through
createClearCollectionAction, and a header delete_sweep button that cleared
every tab of the playlist at once without asking. Remove the header bulk
action end to end, and the unreachable, unconfirmed clear button of the M3U
channel list's recent view, so every clear goes through
createClearCollectionAction. Drop the two i18n keys only those buttons used.

E2E: a shared helper asserts one clear control per page and one confirmation
per press; the M3U, Xtream and Stalker recent tests cancel first (rows stay),
then clear once on the playlist's own recently viewed page.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

.changes/collections-clear-recently-viewed.md

@@ -0,0 +1,8 @@
+---
+type: fix
+area: collections
+---
+
+A playlist's recently viewed page now has a single "Clear recently viewed"
+button, and it always asks before clearing. The second button in the header,
+which cleared every tab at once without asking, is gone.