fix(sqllab): add new tab when add sql query

[stephenLYZ]

SUMMARY

Add new tab when click on +sql query on welcome page.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

before

2021-07-01.4.24.31.mov

after

2021-07-01.4.31.44.mov

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

• Has associated issue: [sqllab] when I try to create a new query using button on homepage then I should see new tab with empty editor #15370
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

Merging #15492 (341b862) into master (e606477) will not change coverage.
The diff coverage is 0.00%.

❗ Current head 341b862 differs from pull request most recent head 96aa314. Consider uploading reports for the commit 96aa314 to get more accurate results

@@           Coverage Diff           @@
##           master   #15492   +/-   ##
=======================================
  Coverage   77.20%   77.20%           
=======================================
  Files         975      975           
  Lines       50842    50842           
  Branches     6728     6728           
=======================================
  Hits        39251    39251           
  Misses      11376    11376           
  Partials      215      215           

Flag	Coverage Δ
javascript	71.76% <0.00%> (ø)

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

Impacted Files	Coverage Δ
...set-frontend/src/views/CRUD/welcome/EmptyState.tsx	87.17% <ø> (ø)
...t-frontend/src/views/CRUD/welcome/SavedQueries.tsx	60.60% <0.00%> (ø)

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[rusackas]

/testenv up

[github-actions]

@rusackas Ephemeral environment spinning up at http://34.216.105.186:8080. Credentials are admin/admin. Please allow several minutes for bootstrapping and startup.

[rusackas]

LGTM!

[github-actions]

Ephemeral environment shutdown and build artifacts deleted.