fix(dashboard): avoid dialing 0.0.0.0 in newHTTPServer. Fixes #3931.

[ItsMattL]

Checklist:

• This is a bugfix
• The title of the PR is (a) conventional with a list of types and scopes found here, (b) states what changed, and (c) suffixes the related issues number. E.g. "fix(controller): Updates such and such. Fixes #1234".
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The code declares endpoint with "0.0.0.0:%d", which is eventually passed to RegisterRolloutServiceHandlerFromEndpoint. This in turn calls grpc.Dial, but 0.0.0.0 is not a valid address to pass to a client. This produces one of the errors documented in issue #3931.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Published E2E Test Results

  4 files    4 suites   3h 26m 1s ⏱️
117 tests 108 ✅  7 💤 2 ❌
470 runs  440 ✅ 28 💤 2 ❌

For more details on these failures, see this check.

Results for commit 6250ff4.

[github-actions]

Published Unit Test Results

2 372 tests   2 372 ✅  3m 4s ⏱️
  129 suites      0 💤
    1 files        0 ❌

Results for commit 6250ff4.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.36%. Comparing base (b9a8811) to head (6250ff4).

Files with missing lines	Patch %	Lines
server/server.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4589      +/-   ##
==========================================
- Coverage   84.37%   84.36%   -0.02%     
==========================================
  Files         164      164              
  Lines       18845    18845              
==========================================
- Hits        15901    15899       -2     
- Misses       2079     2080       +1     
- Partials      865      866       +1     

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