[7141] Bump tailwindcss from 2.2.19 to 4.2.1

[n-lark]

Description

See #7141 (comment)

⚠️ Failed Trivy check

The Trivy check is showing diffs that were not altered in this PR, for example minimatch issues are not new to this branch: https://github.com/FlowFuse/flowfuse/security/code-scanning/57

Ignoring this scan for this PR and will see if dependabot can resolve separately.

Related Issue(s)

Resolves #7141

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production
• Link to Changelog Entry PR, or note why one is not needed.

Labels

• Includes a DB migration? -> add the area:migration label

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.56%. Comparing base (9260a6f) to head (70c2666).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7203   +/-   ##
=======================================
  Coverage   76.56%   76.56%           
=======================================
  Files         405      405           
  Lines       20590    20590           
  Branches     4977     4977           
=======================================
  Hits        15764    15764           
  Misses       4826     4826           

Flag	Coverage Δ
backend	76.56% <ø> (ø)

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[cstns]

the changes are looking good and did a thorough pass of the user facing UI (will raise a follow up task for issues found that were not generated by this migration) and a sanity check of the admin page