Bug 1706124 - wasm: Remove unused reftypes preference. r=lth

Drive-by fix to drop preference for reftypes from StaticPrefList.yaml. This is no
longer used now that the reference types feature gating code is gone.

Depends on D112656

Differential Revision: https://phabricator.services.mozilla.com/D112657

modules/libpref/init/StaticPrefList.yaml

@@ -5792,13 +5792,6 @@
     mirror: always
 #endif  // defined(ENABLE_WASM_RELAXED_SIMD)
 
-#if defined(ENABLE_WASM_REFTYPES)
--   name: javascript.options.wasm_reftypes
-    type: bool
-    value: true
-    mirror: always
-#endif // defined(ENABLE_WASM_REFTYPES)
-
 #if defined(ENABLE_WASM_EXCEPTIONS)
 -   name: javascript.options.wasm_exceptions
     type: bool