fix(docker): pass BUILDPLATFORM env when --platform argument is used

[idsulik]

Fixes: #9284

Description I'm not sure if I fixed the bug correctly, as I couldn't reproduce the bug for myself

User facing changes (remove if N/A) before: if you use --platform={platform} the BUILDPLATFORM argument was not passed to the docker now: it'll pass BUILDPLATFORM

[codecov[bot]]

Codecov Report

Attention: 295 lines in your changes are missing coverage. Please review.

Comparison is base (290280e) 70.48% compared to head (682fb31) 63.61%. Report is 1107 commits behind head on main.

Files	Patch %	Lines
cmd/skaffold/app/cmd/exec.go	16.32%	40 Missing and 1 partial :warning:
cmd/skaffold/app/cmd/filter.go	47.27%	22 Missing and 7 partials :warning:
cmd/skaffold/app/cmd/lsp.go	28.12%	23 Missing :warning:
cmd/skaffold/app/cmd/verify.go	23.33%	23 Missing :warning:
cmd/skaffold/app/cmd/fix.go	51.16%	17 Missing and 4 partials :warning:
cmd/skaffold/app/cmd/inspect_job_manifest_paths.go	60.00%	15 Missing and 1 partial :warning:
cmd/skaffold/app/cmd/inspect_namespaces.go	50.00%	13 Missing and 1 partial :warning:
...md/skaffold/app/cmd/inspect_config_dependencies.go	45.83%	12 Missing and 1 partial :warning:
cmd/skaffold/app/cmd/lint.go	42.85%	12 Missing :warning:
cmd/skaffold/app/cmd/inspect_build_env.go	60.71%	11 Missing :warning:
... and 21 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9291      +/-   ##
==========================================
- Coverage   70.48%   63.61%   -6.87%     
==========================================
  Files         515      635     +120     
  Lines       23150    32775    +9625     
==========================================
+ Hits        16317    20851    +4534     
- Misses       5776    10322    +4546     
- Partials     1057     1602     +545     

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[idsulik]

@ericzzzzzzz Hi! Should I do anything else or I just need to wait?

[ericzzzzzzz]

The original has already been fixed. see https://github.com/GoogleContainerTools/skaffold/issues/9284#issuecomment-1927689782 . So I'm closing this one.