fix(config): fix the type of reject request

[justxuewei]

What this PR does:

The PR #1731 wants to use atomic package, but forgot to change the type of the RejectRequest, this PR fixed this problem.

Which issue(s) this PR fixes:
Fixes #1731

You should pay attention to items below to ensure your pr passes our ci test
We do not merge pr with ci tests failed

• All ut passed (run 'go test ./...' in project root)
• After go-fmt ed , run 'go fmt project' using goland.
• Golangci-lint passed, run 'sudo golangci-lint run' in project root.
• After import formatted, (using imports-formatter to run 'imports-formatter .' in project root, to format your import blocks, mentioned in CONTRIBUTING.md above)
• Your new-created file needs to have apache license at the top, like other existed file does.
• All integration test passed. You can run integration test locally (with docker env). Clone our dubbo-go-samples project and replace the go.mod to your dubbo-go, and run 'sudo sh start_integration_test.sh' at root of samples project root. (M1 Slice is not Support)

[codecov-commenter]

Codecov Report

Merging #1749 (3de90cf) into 3.0 (3cb4d1b) will increase coverage by 0.05%.
The diff coverage is 45.28%.

@@            Coverage Diff             @@
##              3.0    #1749      +/-   ##
==========================================
+ Coverage   42.68%   42.74%   +0.05%     
==========================================
  Files         256      256              
  Lines       14782    14792      +10     
==========================================
+ Hits         6310     6323      +13     
+ Misses       7750     7745       -5     
- Partials      722      724       +2     

Impacted Files	Coverage Δ
common/extension/metadata_remote.go	0.00% <ø> (ø)
config/graceful_shutdown.go	4.00% <0.00%> (ø)
config/graceful_shutdown_config.go	28.88% <0.00%> (ø)
config/metadata_report_config.go	21.68% <0.00%> (-0.82%)	⬇️
config/remote_config.go	7.93% <0.00%> (-0.40%)	⬇️
config/root_config.go	45.78% <0.00%> (+1.40%)	⬆️
registry/protocol/protocol.go	72.42% <0.00%> (ø)
filter/graceful_shutdown/consumer_filter.go	79.16% <50.00%> (ø)
remoting/nacos/builder.go	73.91% <50.00%> (-6.09%)	⬇️
registry/nacos/listener.go	78.26% <62.50%> (+0.29%)	⬆️
... and 8 more

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