Fix input[type="search"] Specifity

Fix search input default styles. Normalize's defaults are a bit too high in specificity, which means we have to slightly increase our specificity too.

Status: **Opened for visibility**
Reviewers: @kpeatt, @ry5n 
JIRA: N/A

## Changes
- Declared `box-sizing` and `-webkit-appearance` on a slightly higher specificity selector for search inputs