Bump sanitize from 5.2.3 to 6.0.0 (#16580)

Fixes nokogumbo/nokogiri conflicts by dropping the nokogumbo gem, as it has
been merged in the nokogiri gem.

Gemfile.lock

@@ -364,11 +364,9 @@ GEM
       net-ssh (>= 2.6.5, < 7.0.0)
     net-ssh (6.1.0)
     nio4r (2.5.7)
-    nokogiri (1.12.0)
+    nokogiri (1.12.2)
       mini_portile2 (~> 2.6.1)
       racc (~> 1.4)
-    nokogumbo (2.0.4)
-      nokogiri (~> 1.8, >= 1.8.4)
     nsa (0.2.8)
       activesupport (>= 4.2, < 7)
       concurrent-ruby (~> 1.0, >= 1.0.2)
@@ -546,10 +544,9 @@ GEM
       fugit (~> 1.1, >= 1.1.6)
     safety_net_attestation (0.4.0)
       jwt (~> 2.0)
-    sanitize (5.2.3)
+    sanitize (6.0.0)
       crass (~> 1.0.2)
-      nokogiri (>= 1.8.0)
-      nokogumbo (~> 2.0)
+      nokogiri (>= 1.12.0)
     scenic (1.5.4)
       activerecord (>= 4.0.0)
       railties (>= 4.0.0)
@@ -770,7 +767,7 @@ DEPENDENCIES
   rubocop (~> 1.18)
   rubocop-rails (~> 2.11)
   ruby-progressbar (~> 1.11)
-  sanitize (~> 5.2)
+  sanitize (~> 6.0)
   scenic (~> 1.5)
   sidekiq (~> 6.2)
   sidekiq-bulk (~> 0.2.0)