Pass ApplicationConfigFiilename when creating deploysource.DeploySource

[Warashi]

What this PR does:

as title

Why we need it:

We have to pass it because plugins need this.

Which issue(s) this PR fixes:

Part of #4980

Does this PR introduce a user-facing change?:

• How are users affected by this change:
• Is this breaking change:
• How to migrate (if breaking change):

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 10 lines in your changes missing coverage. Please review.

Project coverage is 28.17%. Comparing base (fdb9066) to head (5cb4414).
Report is 19 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/app/pipedv1/deploysource/deploysource.go	0.00%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5987      +/-   ##
==========================================
+ Coverage   28.16%   28.17%   +0.01%     
==========================================
  Files         516      516              
  Lines       55895    55897       +2     
==========================================
+ Hits        15743    15751       +8     
+ Misses      38900    38894       -6     
  Partials     1252     1252              

Flag	Coverage Δ
.	23.23% <0.00%> (+0.01%)	⬆️
.-pkg-app-pipedv1-plugin-kubernetes	66.42% <ø> (ø)
.-pkg-app-pipedv1-plugin-kubernetes_multicluster	67.51% <ø> (ø)
.-pkg-app-pipedv1-plugin-wait	35.51% <ø> (ø)
.-pkg-plugin-sdk	50.89% <ø> (ø)
.-tool-actions-gh-release	19.23% <ø> (ø)
.-tool-actions-plan-preview	25.30% <ø> (ø)
.-tool-codegen-protoc-gen-auth	0.00% <ø> (ø)

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[t-kikuc]

[ASK] Where is ApplicationConfigFiilename used?

[Warashi]

@t-kikuc
In the Kubernetes plugin, we use ApplicationConfigFiilename to avoid loading app.pipecd.yaml as a Kubernetes manifest.
The configFilename in the below line comes from ApplicationConfigFiilename.

pipecd/pkg/app/pipedv1/plugin/kubernetes/provider/loader.go

Lines 212 to 214 in 73b52db

	if d.Name() == configFilename {
	return nil
	}

[t-kikuc]

@Warashi Thank you, I got it.

[ffjlabo]

LGTM