feat add tag switch to disable form array of split comma format

[xuerbujia]

Resolve #4629

[kevwan]

Thanks for your contribution! But your modification is too complex, just not splitting the string is OK to accept.

[codecov]

Codecov Report

Attention: Patch coverage is 53.48837% with 20 lines in your changes missing coverage. Please review.

Project coverage is 94.46%. Comparing base (8690859) to head (74e634a).
Report is 259 commits behind head on master.

Files with missing lines	Patch %	Lines
core/mapping/utils.go	17.39%	19 Missing ⚠️
core/mapping/unmarshaler.go	95.00%	1 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
core/mapping/fieldoptions.go	100.00% <ø> (ø)
core/mapping/unmarshaler.go	95.96% <95.00%> (-0.52%)	⬇️
core/mapping/utils.go	96.02% <17.39%> (-3.98%)	⬇️

... and 7 files with indirect coverage changes