chore: Remove GraalVM and 'js' extension checks

[baptistegrimaud]

Closes #608.

Description

Remove the checks and warning logs related to GraalVM and the 'js' language extension from the JavaScript Modules Engine initialization code.

Why were these checks removed?

• GraalVM Check: The code previously warned if GraalVM was not detected, but this is no longer relevant as we've decided to only use OpenJDK (in our Docker images).
• 'js' Extension Check: The 'js' extension is specific to GraalVM and enables JavaScript execution within the JVM. Since OpenJDK does not support GraalVM language extensions, this check is obsolete and has been removed.

Impact

• The engine initialization is now cleaner and does not log unnecessary warnings when running on OpenJDK.
• There is no equivalent check for JavaScript engine support in OpenJDK, as it does not provide GraalVM's polyglot features.

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Pull request overview

This PR removes obsolete GraalVM-specific validation code from the JavaScript Modules Engine initialization. The changes align with the decision to standardize on OpenJDK in Docker images, eliminating unnecessary runtime checks and warning messages.

Key Changes:

• Removed GraalVM version detection and warning logic
• Removed 'js' language extension validation check
• Cleaned up related imports and method calls

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