Fix HF LR schedulers

[ethanwharris]

What does this PR do?

Fixes #1304

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[codecov]

Codecov Report

Merging #1307 (d3ba338) into master (bd62406) will decrease coverage by 0.09%.
The diff coverage is 77.41%.

@@            Coverage Diff             @@
##           master    #1307      +/-   ##
==========================================
- Coverage   91.75%   91.66%   -0.10%     
==========================================
  Files         287      287              
  Lines       12816    12833      +17     
==========================================
+ Hits        11759    11763       +4     
- Misses       1057     1070      +13     

Flag	Coverage Δ
unittests	91.66% <77.41%> (-0.10%)	⬇️

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

Impacted Files	Coverage Δ
flash/text/classification/data.py	100.00% <ø> (ø)
flash/core/model.py	88.80% <50.00%> (+0.43%)	⬆️
flash/core/trainer.py	89.74% <81.48%> (-2.48%)	⬇️
flash/core/serve/interfaces/models.py	95.58% <0.00%> (-4.42%)	⬇️
flash/core/serve/interfaces/http.py	93.67% <0.00%> (-3.80%)	⬇️
flash/core/data/utils.py	89.18% <0.00%> (-1.36%)	⬇️
flash/pointcloud/segmentation/model.py	79.76% <0.00%> (-1.20%)	⬇️
flash/core/utilities/imports.py	91.71% <0.00%> (-1.19%)	⬇️
flash/image/segmentation/model.py	91.76% <0.00%> (-1.18%)	⬇️
flash/core/data/io/input.py	96.03% <0.00%> (-0.80%)	⬇️
... and 3 more

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