Routine to estimate degree for polynomial approximations

[obliviateandsurrender]

Context:

Description of the Change:

Benefits:

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Related GitHub Issues: https://app.shortcut.com/xanaduai/epic/100169?

[github-actions]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.43%. Comparing base (8ebb4fc) to head (2b9e5d4).
⚠️ Report is 14 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8625      +/-   ##
==========================================
- Coverage   99.43%   99.43%   -0.01%     
==========================================
  Files         587      587              
  Lines       61868    61967      +99     
==========================================
+ Hits        61519    61614      +95     
- Misses        349      353       +4     

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