DevTools: NetworkPanel: increase maximum width for filter input.

Currently maximal width is 120px that is too small for non-text filter.

BUG=298834

Review URL: https://codereview.chromium.org/666163002

git-svn-id: svn://svn.chromium.org/blink/trunk@184145 bbb929c8-8fbe-4397-9dbb-9b2b20218538