[Backport v1.22] Bump default image version for agent, dca, ddot

[dd-octo-sts]

Backport 3923040 from #2448.

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What does this PR do?

Bump default image version for agent, cluster-agent, and ddot collector to 7.73.3.

Motivation

What inspired you to submit this pull request?

Additional Notes

Anything else we should know when reviewing?

Minimum Agent Versions

Are there minimum versions of the Datadog Agent and/or Cluster Agent required?

• Agent: vX.Y.Z
• Cluster Agent: vX.Y.Z

Describe your test plan

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Checklist

• PR has at least one valid label: bug, enhancement, refactoring, documentation, tooling, and/or dependencies
• PR has a milestone or the qa/skip-qa label

[fanny-jiang]

/merge

[dd-devflow-routing-codex]

View all feedbacks in Devflow UI.

2026-01-02 19:08:08 UTC ℹ️ Start processing command /merge

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2026-01-02 19:08:13 UTC ℹ️ MergeQueue: waiting for PR to be ready

This pull request is not mergeable according to GitHub. Common reasons include pending required checks, missing approvals, or merge conflicts — but it could also be blocked by other repository rules or settings.
It will be added to the queue as soon as checks pass and/or get approvals.
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2026-01-02 19:36:14 UTC ℹ️ MergeQueue: merge request added to the queue

The expected merge time in v1.22 is approximately 0s (p90).

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2026-01-02 20:37:03 UTC ℹ️ MergeQueue: This merge request was merged

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 37.27%. Comparing base (9fdc70a) to head (89f00f9).

Additional details and impacted files

@@           Coverage Diff           @@
##            v1.22    #2449   +/-   ##
=======================================
  Coverage   37.27%   37.27%           
=======================================
  Files         290      290           
  Lines       24705    24705           
=======================================
  Hits         9209     9209           
  Misses      14783    14783           
  Partials      713      713           

Flag	Coverage Δ
unittests	37.27% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
pkg/images/images.go	97.58% <ø> (ø)

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