fix(collapse): remove unnecessary inherit

- Remove unnecessary `inherit` property, which causes issues when custom widths are used, including percentage based widths

Closes #6164
Fixes #6163

src/collapse/collapse.js

@@ -18,13 +18,11 @@ angular.module('ui.bootstrap.collapse', [])
           horizontal = !!('horizontal' in attrs);
           if (horizontal) {
             css = {
-              width: 'auto',
-              height: 'inherit'
+              width: 'auto'
             };
             cssTo = {width: '0'};
           } else {
             css = {
-              width: 'inherit',
               height: 'auto'
             };
             cssTo = {height: '0'};