[Java][Spring] Bump jackson-databind-nullable to 0.2.11 in the Spring Boot 4 templates

[Sekator778]

The three JavaSpring pom-sb4 templates still pin jackson-databind-nullable 0.2.8, #24501 bumped only the sb3 ones. 0.2.8 has no Jackson 3 module, so JsonNullable fields don't serialize in generated Spring Boot 4 apps (you get {"present":true,"undefined":false} instead of the value). This bumps them to 0.2.11 and regenerates the two affected samples. Checked it with generated spring-boot, spring-cloud and spring-http-interface projects.

Fixes #24975

@cachescrubber @welshm @MelleD @atextor @manedev79 @javisst @borsch @banlevente @Zomzog @martin-mfg @KannaKim

PR checklist

• Read the contribution guidelines.
• Run the following to build the project and update samples:

  ./mvnw clean package || exit
  ./bin/generate-samples.sh ./bin/configs/*.yaml || exit
  ./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.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

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Summary by cubic

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^{Written for commit a44c054. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 5 files

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