[Java] Replace if with ? in Generated toIndentedString-methods

[Chrimle]

Refactors all generated Java classes' toIndentedString-method to internally use Ternary Operator for null-checking, instead of a conventional if-statement.
NOTE: This change should make the method smaller, but will be equivalent in terms of functionality and performance.

Example:

Before:

private String toIndentedString(Object o) {
    if (o == null) {
        return "null";
    }
    return o.toString().replace("\n", "\n    ");
}

After:

private String toIndentedString(Object o) {
    return o == null ? "null" : o.toString().replace("\n", "\n    ");
}

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• Run the following to build the project and update samples:

  ./mvnw clean package || exit
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  ./bin/utils/export_docs_generators.sh || exit
  

  (For Windows users, please run the script in WSL)
  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
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---

Summary by cubic

Refactor toIndentedString across all Java templates to use a single-line ternary null check and regenerate samples across Java generators. Behavior is unchanged ("null" for null; toString() with newline indentation otherwise).

^{Written for commit 2909915. Summary will update on new commits.}

[Chrimle]

Only ran j* samples so far, will update tomorrow 👍

[Chrimle]

On second thought, wouldn't it just be simpler with ?: syntax instead?

[Chrimle]

To be completely honest, I don't know if these methods should even be kept at all... that's a lot of boilerplate just to make the output prettier...

[cubic-dev-ai]

No issues found across 3000 files

Note: This PR contains a large number of files. cubic only reviews up to 75 files per PR, so some files may not have been reviewed.