fix(text-field): Remove unnecessary styling on label in disabled state

[lynnmercier]

The label already sets bottom: 8px in mdc-text-field-label.scss. So it seems unnecessary to override that in mdc-text-field--disabled

[codecov-io]

Codecov Report

Merging #2058 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2058      +/-   ##
==========================================
- Coverage   99.43%   99.43%   -0.01%     
==========================================
  Files          84       84              
  Lines        3720     3718       -2     
  Branches      485      485              
==========================================
- Hits         3699     3697       -2     
  Misses         21       21

Impacted Files	Coverage Δ
packages/mdc-slider/foundation.js	100% <0%> (ø)	⬆️
packages/mdc-menu/foundation.js
packages/mdc-menu/index.js
packages/mdc-menu/constants.js
packages/mdc-menu/simple/index.js	100% <0%> (ø)
packages/mdc-menu/simple/foundation.js	99.26% <0%> (ø)
packages/mdc-menu/simple/constants.js	100% <0%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 793dcdf...497e0fa. Read the comment docs.

[kfranqueiro]

Hm. Yeah I'm not sure why that style was there. Also I think removing this line might also allow you to remove lines for disabled box/outlined which are simply there to override this back to the value they would otherwise have inherited?

[lynnmercier]

Sure, removed extra styling from the disabled outlined and box...and I removed some extra styling from the dense box