fix: change buttons to be only save and overwrite

[hughhhh]

SUMMARY

Change the naming of the save dataset modal buttons when in explore:

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 #20851 (4cbb325) into master (e3c6380) will not change coverage.
The diff coverage is n/a.

❗ Current head 4cbb325 differs from pull request most recent head 4902cc1. Consider uploading reports for the commit 4902cc1 to get more accurate results

@@           Coverage Diff           @@
##           master   #20851   +/-   ##
=======================================
  Coverage   66.30%   66.30%           
=======================================
  Files        1757     1757           
  Lines       66860    66860           
  Branches     7077     7077           
=======================================
  Hits        44332    44332           
  Misses      20719    20719           
  Partials     1809     1809           

Flag	Coverage Δ
javascript	51.95% <ø> (ø)

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

Impacted Files	Coverage Δ
...re/components/controls/DatasourceControl/index.jsx	75.24% <ø> (ø)

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