Remove deploying detection logic from drift detector

[nghialv]

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

NONE

[pipecd-bot]

Code coverage for golang is 33.96%. This pull request increases coverage by 0.05%.

File	Function	Base	Head	Diff
pkg/app/piped/driftdetector/kubernetes/detector.go	detector.listGroupedApplication	--	0.00%	+0.00%
pkg/app/api/grpcapi/piped_api.go	PipedAPI.ReportApplicationDeployingStatus	0.00%	0.00%	+0.00%
pkg/app/piped/driftdetector/kubernetes/detector.go	detector.check	0.00%	0.00%	+0.00%
pkg/app/piped/driftdetector/kubernetes/detector.go	detector.listApplications	0.00%	--	+-0.00%
pkg/app/piped/driftdetector/kubernetes/detector.go	makeDeployingState	0.00%	--	+-0.00%

[nakabonne]

/lgtm

[khanhtc1202]

🚀
/approve

[pipecd-bot]

This pull request is APPROVED by khanhtc1202.

Approvers can cancel the approval by writing /approve cancel in a comment. Any additional commits also will change this pull request to be not-approved.