Add logo version for dark backgrounds

[Yndira-E]

Description

On https://github.com/FlowFuse/flowfuse/pull/4924/files the logo was deleted, and now there's no logo in the top bar.

I’ve just added the latest version and performed a ‘find/replace’ search for the name of the old file.

Related Issue(s)

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

Labels

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

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 78.63%. Comparing base (be3af14) to head (8e22980).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
forge/routes/api-docs.js	50.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4930   +/-   ##
=======================================
  Coverage   78.63%   78.63%           
=======================================
  Files         324      324           
  Lines       15265    15265           
  Branches     3507     3507           
=======================================
  Hits        12003    12003           
  Misses       3262     3262           

Flag	Coverage Δ
backend	78.63% <50.00%> (ø)

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[cstns]

Nice catch @Yndira-E, This should have been caught locally but the clean webpack plugin served us a nasty error

[cstns]

linking here #4931