Redesign the UI to make the issue summary table more useful, by:

Making issue descriptions expand so that full content is viewable on click. This change allows the user to conveniently see full issue descriptions in-table, without having to click the description and be redirected to the comment itself.

A new div in review_issue_summary_table.html contains full comment text and is initially hidden.

The CSS class, 'issue-summary-collapsed,' is applied to this hidden div when the summary is collapsed. JS methods, onPreviewClicked and onFullClicked handle user clicks.

Adding buttons to fix/drop issues in the issue summary table.

Each entry in the issue summary table now has a set of Fix and Drop buttons, visible when expanded, from which you can address the issue and the status of the issue will update everywhere. You can also continue to use the previously existing buttons in the review to fix, drop, or reopen, and the table will be updated accordingly.

Manual testing (expandable descriptions):

- Added long (past the 20 word cutoff mark) comments to a review request.

- Able to click the description in the issue summary table to see the full comment text.

- If the full text is being displayed, able to switch back to the 20 word version upon click.

(buttons):

- Clicking the Fix or Drop button when a description is expanded fades the issue out of the table and updates its status at the actual place in the review. It stays upon refreshing the page.
Added new commentIssueBar unit tests and ran js-tests. All passed.