[CONTP-1780] Add untaint controller config to datadog operator

[adel121]

What this PR does / why we need it:

Adds untaintController.enabled to allow enabling untaint controller, in addition to other configuration options documented in readme.md.

Special notes for your reviewer:

After merging this PR, we should bump operator chart version in datadog chart dependency in this PR and merge it.

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• All commits are signed and show as "Verified" on GitHub (see: signing commits)
• Chart Version semver bump label has been added (use <chartName>/minor-version, <chartName>/patch-version, or <chartName>/no-version-bump)
• For datadog or datadog-operator chart or value changes, update the test baselines (run: make update-test-baselines)
• For datadog chart changes, received ✅ from a member of your team

GitHub CI takes care of the below, but are still required:

• Documentation has been updated with helm-docs (run: .github/helm-docs.sh)
• CHANGELOG.md has been updated
• Variables are documented in the README.md

[adel121]

/merge

[gh-worker-devflow-routing-ef8351]

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2026-07-09 13:19:38 UTC ℹ️ Start processing command /merge

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2026-07-09 13:19:44 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in main is approximately 53m (p90).

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2026-07-09 13:26:54 UTC 🚨 MergeQueue: This merge request is in error

mergequeue build completed successfully, but the github api returned an error while merging the pr.
It's probably because:

• target branch of PR is restricted to only allow up-to-date branches, but the pr is now outdated

Details

Error: PUT https://api.github.com/repos/DataDog/helm-charts/pulls/2773/merge: 405 Required status check "pr-validated" is expected. [] (Request ID: CCCF:128753:18DF89B:5714B9A:6A4FA193)

FullStacktrace:
activity error (type: github.GithubService_MergePullRequest, scheduledEventID: 50, startedEventID: 51, identity: 1@github-worker-65778c9c86-7j2z7@): PUT https://api.github.com/repos/DataDog/helm-charts/pulls/2773/merge: 405 Required status check "pr-validated" is expected. [] (Request ID: CCCF:128753:18DF89B:5714B9A:6A4FA193) (type: GitFailure, retryable: false): PUT https://api.github.com/repos/DataDog/helm-charts/pulls/2773/merge: 405 Required status check "pr-validated" is expected. [] (type: ErrorResponse, retryable: true)