Remove buggy chmod directive

[L3n41c]

What this PR does / why we need it:

Remove a buggy

chmod -R 744 /etc/datadog-agent

in the init container of the cluster agent:

• it recursively sets the execution bit for the user, even on non-executable, non-directory files.
• it doesn’t set the directory search bit for group and others on directories.

This chmod was introduced by #1096 to workaround an issue introduced by DataDog/datadog-agent#16347 and DataDog/datadog-agent#18069.
Let’s rather fix the issue at its root cause: inside the docker image thanks to DataDog/datadog-agent#19673.

Which issue this PR fixes

• fixes CONS-5810

Special notes for your reviewer:

Checklist

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

• Chart Version bumped
• Documentation has been updated with helm-docs (run: .github/helm-docs.sh)
• CHANGELOG.md has been updated
• Variables are documented in the README.md
• For Datadog Operator chart or value changes update the test baselines (run: make update-test-baselines)