@Ramanth, @saigiridhar21, @wing328

This PR removes an annoying warning. Since generated models are used when parsing REST responses into R6 objects for the R language client, the ". If you did not manually initialize {{{classname}}}, this may already be overwritten by an enum loaded from a JSON config." part of the warning is usually true, meaning that any responses that include enums will invariably print confusing warning messages.

I left the check to ensure that the enum is populated either with an acceptable value or DUMMY_ENUM so that JSON parsing continues to work in the same way it currently does.

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Summary by cubic

Removed the DUMMY_ENUM initialization warning in R enum models to stop confusing messages when parsing API responses. Validation still enforces allowed values, and the DUMMY_ENUM fallback behavior is unchanged.

^{Written for commit 679b8ff. Summary will update on new commits.}