chore: remove deprecated apis copy_dash, save_dash and add_slices

[dpgaspar]

SUMMARY

Removes deprecated APIs:

• /superset/copy_dash/int:dashboard_id/
• /superset/save_dash/int:dashboard_id/
• /superset/add_slices/int:dashboard_id/

Effort on removing deprecated API from /superset: #24332

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• 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 #24353 (1504d19) into master (c09b8c6) will increase coverage by 1.81%.
The diff coverage is n/a.

❗ Current head 1504d19 differs from pull request most recent head 7fa6c97. Consider uploading reports for the commit 7fa6c97 to get more accurate results

@@            Coverage Diff             @@
##           master   #24353      +/-   ##
==========================================
+ Coverage   67.18%   68.99%   +1.81%     
==========================================
  Files        1903     1903              
  Lines       74275    74196      -79     
  Branches     8110     8110              
==========================================
+ Hits        49898    51194    +1296     
+ Misses      22265    20890    -1375     
  Partials     2112     2112              

Flag	Coverage Δ
hive	54.04% <ø> (?)
javascript	55.62% <ø> (ø)
mysql	79.30% <ø> (-0.04%)	⬇️
postgres	79.38% <ø> (-0.04%)	⬇️
presto	53.97% <ø> (?)
python	83.35% <ø> (+3.79%)	⬆️
sqlite	77.89% <ø> (-0.04%)	⬇️
unit	54.46% <ø> (?)

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

Impacted Files	Coverage Δ
superset-frontend/src/dashboard/actions/hydrate.js	2.04% <ø> (ø)
superset/views/core.py	74.75% <ø> (-0.78%)	⬇️

... and 99 files with indirect coverage changes

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[michael-s-molina]

LGTM