Chore: refactor kebab menu item naming

[cstns]

Description

Refactor to replace ff-list-item with ff-kebab-item across components and tests for improved structure and consistency.

Related Issue(s)

closes #6374

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 76.42%. Comparing base (1c343d7) to head (c7873e2).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6490   +/-   ##
=======================================
  Coverage   76.42%   76.42%           
=======================================
  Files         396      396           
  Lines       19890    19890           
  Branches     4771     4771           
=======================================
  Hits        15201    15201           
  Misses       4689     4689           

Flag	Coverage Δ
backend	76.42% <ø> (ø)

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[Steve-Mcl]

@cstns are you looking at e2e fails?

  │ ✖  brokers/3rd-party-broker.spec.js         00:09        5        4        1        -        - │
  ├────────────────────────────────────────────────────────────────────────────────────────────────┤
  │ ✖  brokers/brokers.spec.js                  00:33       12        7        5        -        - │
  
  
  ✖  2 of 29 failed (7%)  

[Steve-Mcl]

all good

[Steve-Mcl]

Was an e2e test fail. Merging main before digging.