Moderation settings fixes (#1336)

* Default isAdultContentEnabled to false on all devices.

The original intent of setting the default based on the device was
to make the maximally-permissive choice. It turns out this was a
mistake as it created sync issues between devices; users would be
confused by the lack of congruity between them. We have to go with
false by default to ensure sync is retained.

* Update preferences model to use new sdk api

* Delete dead code

* Dont show the iOS adult content warning in content filtering settings if adult content is enabled

* Bump @atproto/api@0.6.8

* Codebase style consistency

yarn.lock

@@ -45,13 +45,13 @@
     tlds "^1.234.0"
     typed-emitter "^2.1.0"
 
-"@atproto/api@^0.6.6":
-  version "0.6.6"
-  resolved "https://registry.yarnpkg.com/@atproto/api/-/api-0.6.6.tgz#c1bfdb6bc7dee9cdba1901cde0081c2d422d7c29"
-  integrity sha512-j+yNTjllVxuTc4bAegghTopju7MdhczLXWvWIli40uXwCzQ3JjS1mFr/47eETtysib2phWYQvfhtCrqQq6AAig==
+"@atproto/api@^0.6.8":
+  version "0.6.8"
+  resolved "https://registry.yarnpkg.com/@atproto/api/-/api-0.6.8.tgz#fe77f3ab2e7a815edca1357b0a89a7496be8f764"
+  integrity sha512-WmXpIbO79f85UA8AzvvSqKibojBXN1HT3KEHhUOqXJRW8X1trYijgWIXwhnxhoBQXgiQfzKG7HdORvRjmRSLoQ==
   dependencies:
     "@atproto/common-web" "*"
-    "@atproto/uri" "*"
+    "@atproto/syntax" "*"
     "@atproto/xrpc" "*"
     tlds "^1.234.0"
     typed-emitter "^2.1.0"
@@ -317,6 +317,13 @@
     uint8arrays "3.0.0"
     zod "^3.21.4"
 
+"@atproto/syntax@*":
+  version "0.1.0"
+  resolved "https://registry.yarnpkg.com/@atproto/syntax/-/syntax-0.1.0.tgz#f13b9dad8d13342cc54295ecd702ea13c82c9bf0"
+  integrity sha512-Ktui0qvIXt1o1Px1KKC0eqn69MfRHQ9ok5EwjcxIEPbJ8OY5XqkeyJneFDIWRJZiR6vqPHfjFYRUpTB+jNPfRQ==
+  dependencies:
+    "@atproto/common-web" "*"
+
 "@atproto/uri@*":
   version "0.1.0"
   resolved "https://registry.yarnpkg.com/@atproto/uri/-/uri-0.1.0.tgz#1cb4695d2f1766ec8d542af6a495a416f6f6c214"