chore: add loading in route page

[CP3cham]

Please answer these questions before submitting a pull request, or your PR will get closed.

Why submit this pull request?

• Bugfix
• New feature provided
• Improve performance
• Backport patches

Related issues

fix/resolve #2222

Checklist:

add loading status in route page when the Internet is slow

[juzhiyuan]

cc @guoqqqi to have a review

[guoqqqi]

please add the test

[guoqqqi]

@CP3cham ping
Did you have any problems?

[codecov-commenter]

Codecov Report

Merging #2287 (f245c1b) into master (e0d92c4) will decrease coverage by 1.80%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2287      +/-   ##
==========================================
- Coverage   69.91%   68.10%   -1.81%     
==========================================
  Files         184      127      -57     
  Lines        7279     3374    -3905     
  Branches      830      830              
==========================================
- Hits         5089     2298    -2791     
+ Misses       1896     1076     -820     
+ Partials      294        0     -294     

Flag	Coverage Δ
backend-e2e-test	?
backend-e2e-test-ginkgo	?
backend-unit-test	?
frontend-e2e-test	68.10% <100.00%> (-0.06%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
web/src/pages/Route/List.tsx	82.84% <100.00%> (ø)
web/src/helpers.tsx	70.49% <0.00%> (-3.28%)	⬇️
api/internal/filter/logging.go
api/internal/handler/data_loader/route_import.go
api/internal/core/storage/etcd.go
api/internal/handler/stream_route/stream_route.go
api/cmd/version.go
api/internal/core/server/store.go
api/internal/core/server/http.go
api/internal/core/entity/entity.go
... and 49 more

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[zaunist]

LGTM

[guoqqqi]

LGTM! Thank you for your contribution