ci: fix sauce-connect-proxy version

Somehow the requested and resolved versions of `sauce-connect-proxy` got desynced and downgraded to 4.8.1 in 68dae53. This reverts that change and bumps it back up to 4.9.1 which appears to fix Saucelabs CI.

(cherry picked from commit 5495819)

Author: dgp1130

yarn.lock

@@ -11944,7 +11944,7 @@ sass@^1.69.5:
 
 "sauce-connect-proxy@https://saucelabs.com/downloads/sc-4.9.1-linux.tar.gz":
   version "0.0.0"
-  resolved "https://saucelabs.com/downloads/sc-4.8.1-linux.tar.gz#9c16682e4c9716734432789884f868212f95f563"
+  resolved "https://saucelabs.com/downloads/sc-4.9.1-linux.tar.gz#9310bc860f7870a1f872b11c4dc6073a1ad34e5e"
 
 saucelabs@^1.5.0:
   version "1.5.0"