fix numberinput styling on gradebook late policies tab
fix numberinput styling on gradebook late policies tab

fixes: CNVS-37609

Test Plan:
1. Navigate to gradezilla and open settings modal
2. Observe that number inputs match comps
  - No inner border
  - No inner bottom margin
  - Auto line height
  - No inner box shadow

Change-Id: I11e43a9169305677ac92802fb871039b2d5ded50
Reviewed-on: https://gerrit.instructure.com/117535
Tested-by: Jenkins
Reviewed-by: Jeremy Neander <20252aad5efdc666f083d82ab63ed0f9f72a043e@instructure.com>
Reviewed-by: Matt Taylor <6523858f0187e99881b3902a31b8a85366f3df97@instructure.com>
QA-Review: Anju Reddy <851202533fb1f0b615e4547ba226c76996d060dd@instructure.com>
Product-Review: Pert Eilers <b5114c9284a53681de3b74bf12eb2d826ceca963@instructure.com>

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