fix: Wrong behavior of CurrentTargetFirst/NextTargetFirst in target manager

[weiliu1031]

issue: #31162
pr: #31379

when give scope CurrentTargetFirst/NextTargetFirst, it's expected to scan both current and next target.

This PR fixed wrong behavior of CurrentTargetFirst/NextTargetFirst in target manager, which may cause unexpected task generated, and load collection may stuck forever due to dirty leader view.

[mergify]

@weiliu1031 Please associate the related pr of master to the body of your Pull Request. (eg. “pr: #”)

[mergify]

@weiliu1031 E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.

[weiliu1031]

/run-cpu-e2e

[congqixia]

/lgtm

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: congqixia, weiliu1031

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[mergify]

@weiliu1031 E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.

[weiliu1031]

/run-cpu-e2e

[mergify]

@weiliu1031 E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.

[mergify]

@weiliu1031 E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.

[weiliu1031]

/run-cpu-e2e

[codecov]

Codecov Report

Attention: Patch coverage is 99.03846% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 81.05%. Comparing base (3254a14) to head (31b6fa0).
Report is 3 commits behind head on 2.4.

Additional details and impacted files

@@            Coverage Diff            @@
##              2.4   #31378     +/-   ##
=========================================
  Coverage   81.05%   81.05%             
=========================================
  Files         980      980             
  Lines      144653   143441   -1212     
=========================================
- Hits       117248   116270    -978     
+ Misses      23529    23278    -251     
- Partials     3876     3893     +17     

Files	Coverage Δ
internal/querycoordv2/meta/target_manager.go	87.14% <99.03%> (+3.51%)	⬆️

... and 174 files with indirect coverage changes

[czs007]

/lgtm