deps: Bump oblt-cli version to 7.31.6

[elastic-observability-automation]

deps: Bump oblt-cli version

deps(oblt-cli): Bump oblt-cli version to 7.31.6

1 file(s) updated with "7.31.6\n": * oblt-cli/setup/.default-oblt-cli-version

7.31.6

### Changes

## 📚 Documentation

- docs: Add OIDC not authorized issue @kuisathaverat (#130919)

**Full Changelog**: https://github.com/elastic/observability-test-environments/compare/7.31.5...7.31.6

For more information, please visit:
  * clusters docs at https://ela.st/oblt-clusters
  * oblt-cli docs at https://ela.st/oblt-cli
  * oblt-robot docs at https://ela.st/oblt-robot
  * Serverless docs at https://ela.st/oblt-serverless

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