Remove unreachable_from_main linter rule (#120110)

* Remove unreachable_from_main linter rule

* Comment out

* Update analysis_options.yaml

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Co-authored-by: Michael Goderbauer <goderbauer@google.com>

Author: srawlins

analysis_options.yaml

@@ -222,7 +222,7 @@ linter:
     - unnecessary_string_interpolations
     - unnecessary_this
     - unnecessary_to_list_in_spreads
-    - unreachable_from_main
+    # - unreachable_from_main # Do not enable this rule until it is un-marked as "experimental" and carefully re-evaulated.
     - unrelated_type_equality_checks
     - unsafe_html
     - use_build_context_synchronously