Playwright fixes and improvements (#28925)

* Fix playwright-image-updates.yaml workflow

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Add `X-Run-All-Tests` label for running all tests

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Ignore failing tests in stale-screenshot-reporter.ts to avoid confusing errors

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

---------

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

.github/labels.yml

@@ -210,6 +210,9 @@
 - name: "X-Upcoming-Release-Blocker"
   description: "This does not affect the current release cycle but will affect the next one"
   color: "e99695"
+- name: "X-Run-All-Tests"
+  description: "When applied to PRs, it'll run the full gamut of end-to-end tests on the PR"
+  color: "ff7979"
 - name: "Z-Actions"
   color: "ededed"
 - name: "Z-Cache-Confusion"