Remove Switch Access flag and extend text improvement flag

AX-Relnotes: n/a.
Bug: None.
Change-Id: I88574e566d707bea67304fefa96ccda13c6d58d5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2422461
Commit-Queue: Akihiro Ota <akihiroota@chromium.org>
Auto-Submit: Anastasia Helfinstein <anastasi@google.com>
Reviewed-by: Akihiro Ota <akihiroota@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809100}

chrome/browser/flag-metadata.json

@@ -1482,15 +1482,10 @@
     "owners": [ "chrishall", "//ui/accessibility/OWNERS" ],
     "expiry_milestone": 87
   },
-  {
-    "name": "enable-experimental-accessibility-switch-access",
-    "owners": [ "anastasi@google.com", "//ui/accessibility/OWNERS" ],
-    "expiry_milestone": 86
-  },
   {
     "name": "enable-experimental-accessibility-switch-access-text",
     "owners": [ "anastasi@google.com", "//ui/accessibility/OWNERS" ],
-    "expiry_milestone": 87
+    "expiry_milestone": 90
   },
   {
     "name": "enable-experimental-cookie-features",