Update stale 'Hermes V1' comments (#56757)

Summary:
Pull Request resolved: #56757

Update comments that still say 'Hermes V1' as if it is an opt-in feature.
Since Hermes (formerly called Hermes V1) is now the only supported engine:
- hermes-engine.podspec: drop 'when using Hermes V1' from hermesc note
- PathUtils.kt: rewrite the hermesc path comment to drop the 'opted in to Hermes V1' phrasing
- hermes-engine/build.gradle.kts: 'Hermes V1 by default...' -> 'Hermes by default...'

## Changelog:
[Internal] -

Reviewed By: cortinico

Differential Revision: D104649634

fbshipit-source-id: 9b0a05ed013c7ba908c7abe467d5e3c1c3c2f26c

Author: cipolleschi

packages/gradle-plugin/react-native-gradle-plugin/src/main/kotlin/com/facebook/react/utils/PathUtils.kt

@@ -123,11 +123,9 @@ private fun detectCliFile(
  * 1. The path provided by the `hermesCommand` config in the `react` Gradle extension
  * 2. The file located in `node_modules/react-native/sdks/hermes/build/bin/hermesc`. This will be
  *    used if the user is building Hermes from source.
- * 3. The file located in `node_modules/react-native/sdks/hermesc/%OS-BIN%/hermesc` where `%OS-BIN%`
- *    is substituted with the correct OS arch. This will be used if the user is using a precompiled
- *    hermes-engine package. Or, if the user has opted in to use Hermes V1, the used file will be
- *    located in `node_modules/hermes-compiler/%OS-BIN%/hermesc` where `%OS-BIN%` is substituted
- *    with the correct OS arch.
+ * 3. The file located in `node_modules/hermes-compiler/%OS-BIN%/hermesc` where `%OS-BIN%` is
+ *    substituted with the correct OS arch. This is used when Hermes V1 is consumed as a prebuilt
+ *    package via the `hermes-compiler` npm package.
  * 4. Fails otherwise
  */
 internal fun detectOSAwareHermesCommand(

packages/react-native/sdks/hermes-engine/hermes-engine.podspec

@@ -65,7 +65,7 @@ Pod::Spec.new do |spec|
     end
 
     # When using the local prebuilt tarball, it should include hermesc compatible with the used VM.
-    # In other cases, when using Hermes V1, the prebuilt versioned binaries can be used.
+    # In other cases, the prebuilt versioned Hermes V1 hermesc binaries from the hermes-compiler npm package can be used.
     if source_type != HermesEngineSourceType::LOCAL_PREBUILT_TARBALL
       hermes_compiler_path = File.dirname(Pod::Executable.execute_command('node', ['-p',
         "require.resolve(\"hermes-compiler\", {paths: [\"#{react_native_path}\"]})", __dir__]).strip