Hide dynamic field for describing collection

[xiaocai2333]

/kind improvement

1. DescribeCollection does not return $meta column.
2. For insert dynamic data, add a new field data with is_dynamic = true.

[czs007]

/approve
/lgtm

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: czs007, xiaocai2333

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[xiaocai2333]

rerun ut

[codecov]

Codecov Report

Merging #24312 (18d54d8) into master (d16e18f) will increase coverage by 0.41%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master   #24312      +/-   ##
==========================================
+ Coverage   81.85%   82.26%   +0.41%     
==========================================
  Files         769      758      -11     
  Lines      101869    99642    -2227     
==========================================
- Hits        83382    81971    -1411     
+ Misses      15451    14641     -810     
+ Partials     3036     3030       -6     

Impacted Files	Coverage Δ
internal/proxy/task.go	85.76% <100.00%> (+0.02%)	⬆️
internal/proxy/task_insert.go	68.88% <100.00%> (+1.78%)	⬆️
internal/proxy/util.go	90.97% <100.00%> (ø)

... and 182 files with indirect coverage changes

[czs007]

/lgtm