Revert "Improve validation for format parameter in Oembed request"

[edlib-oddarne]

Reverts #3273

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 42.99%. Comparing base (386c2ec) to head (2a524ad).
⚠️ Report is 4 commits behind head on master.

❗ There is a different number of reports uploaded between BASE (386c2ec) and HEAD (2a524ad). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (386c2ec)	HEAD (2a524ad)
	2	1

Additional details and impacted files

@@              Coverage Diff              @@
##             master    #3275       +/-   ##
=============================================
- Coverage     61.05%   42.99%   -18.07%     
+ Complexity     3588      945     -2643     
=============================================
  Files           410      171      -239     
  Lines         15592     3752    -11840     
=============================================
- Hits           9520     1613     -7907     
+ Misses         6072     2139     -3933     

Components	Coverage Δ
Content Author	∅ <ø> (∅)
Hub	42.99% <0.00%> (-0.17%)	⬇️

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