[dashboard] increase tab count limit

[graceguo-supercat]

CATEGORY

Choose one

• Bug Fix
• Enhancement (new features, refinement)
• Refactor
• Add tests
• Build / Development Environment
• Documentation

SUMMARY

Currently dashboard only allow up to 7 tabs in one tab container. This PR is to increase the limit to 10.

TEST PLAN

Manual test.

ADDITIONAL INFORMATION

• Has associated issue:
• Changes UI
• Requires DB Migration.
• Confirm DB Migration upgrade and downgrade tested.
• Introduces new feature or API
• Removes existing feature or API

REVIEWERS

@etr2460 @williaster

[codecov-io]

Codecov Report

Merging #9640 into master will decrease coverage by 0.21%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #9640      +/-   ##
==========================================
- Coverage   70.52%   70.31%   -0.22%     
==========================================
  Files         574      182     -392     
  Lines       30152    17700   -12452     
  Branches     3060        0    -3060     
==========================================
- Hits        21265    12445    -8820     
+ Misses       8776     5255    -3521     
+ Partials      111        0     -111     

Flag	Coverage Δ
#cypress	?
#javascript	?
#python	70.31% <ø> (-0.26%)	⬇️

Impacted Files	Coverage Δ
superset/views/database/mixins.py	58.92% <0.00%> (-21.43%)	⬇️
superset/utils/cache.py	45.83% <0.00%> (-20.84%)	⬇️
superset/db_engine_specs/postgres.py	80.00% <0.00%> (-15.00%)	⬇️
superset/db_engine_specs/mysql.py	78.26% <0.00%> (-13.05%)	⬇️
superset/views/database/api.py	83.90% <0.00%> (-3.45%)	⬇️
superset/models/core.py	84.47% <0.00%> (-2.39%)	⬇️
superset/security/manager.py	88.77% <0.00%> (-0.35%)	⬇️
superset/views/core.py	75.01% <0.00%> (-0.23%)	⬇️
superset/connectors/sqla/models.py	88.37% <0.00%> (-0.16%)	⬇️
...uperset-frontend/src/utils/getClientErrorObject.js
... and 390 more

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[etr2460]

We should probably make sure @mistercrunch @rusackas and @betodealmeida at least get pinged on this so they're aware of the design change.

If everyone's in agreement, then lgtm. otherwise we might consider a config var

[rusackas]

The intent in the update for the tabs, as I recall, is to let them take up whatever width they need, and (much like Chrome's tabs) tack on a dropdown menu if they overflow the available real estate. In the light of that, I don't think tweaking the number of tabs for the current design should make much difference in the long run.

[rusackas]

But thank you for pointing out this kind of thing, I sincerely appreciate it.