refactor: Remove obsolete FromQuantityInfo method

[angularsen]

Fixup of #1555

[lipchev]

This was just for backwards compatibility, I don't think this method was [Obsolete] in v5- so instead of breaking the build, i figured we'd issue a deprecation warning. But if you think we don't need it, I'm perfectly fine with it..

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93%. Comparing base (5131d24) to head (3ff3fda).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@ Coverage Diff @@## master #1574 +/- ##
======================================
- Coverage 93% 93% -1% 
======================================
Files 311 311 Lines 28781 28780 -1 ======================================
- Hits 26864 26863 -1 
Misses 1917 1917 

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[angularsen]

Let's remove stuff now that we have the chance in v6, I'd rather add it back if there was something we missed.

[angularsen]

Obsoleted in v5: #1577