fix(username_regex): cp consumer name regx different with dp

[zaunist]

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

What changes will this PR take into?

APISIX support consumer name start with number, but APISIX-Dashboard does't support. Does the APISIX-Dashboard need to support consumer that start with number.
And there is the APISIX regex https://github.com/apache/apisix/blob/master/apisix/schema_def.lua#L693

After change:

Related issues

fix/resolve #2196

Checklist:

• Did you explain what problem does this PR solve? Or what new features have been added?
• Have you added corresponding test cases?
• Have you modified the corresponding document?
• Is this PR backward compatible? If it is not backward compatible, please discuss on the mailing list first

[zaunist]

cc @liuxiran @bzp2010 @LiteSun @juzhiyuan

[codecov-commenter]

Codecov Report

Merging #2232 (4a994e9) into master (cc1e5d4) will decrease coverage by 0.05%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2232      +/-   ##
==========================================
- Coverage   68.07%   68.02%   -0.06%     
==========================================
  Files         127      127              
  Lines        3352     3359       +7     
  Branches      824      826       +2     
==========================================
+ Hits         2282     2285       +3     
- Misses       1070     1074       +4     

Flag	Coverage Δ
frontend-e2e-test	68.02% <ø> (-0.06%)	⬇️

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

Impacted Files	Coverage Δ
web/src/pages/Consumer/components/Step1.tsx	100.00% <ø> (ø)
...pages/Route/components/Step1/MatchingRulesView.tsx	74.73% <0.00%> (-2.19%)	⬇️
web/src/pages/Route/transform.ts	77.41% <0.00%> (-1.27%)	⬇️
web/src/helpers.tsx	73.77% <0.00%> (+3.27%)	⬆️

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[juzhiyuan]

LGTM

[zaunist]

cc @okaybase

[okaybase]

cc @okaybase

the tip message is updated~

[zaunist]

cc @okaybase

the tip message is updated~

thanks