Applying filter in issue tracker should reset page to 1 (BB-15812)

If you are scrolling issues and navigate to a page > 1, when you click on a value (for example "Milestone") to apply another filter, the URL value keeps the same page, which may be invalid for the new filter. For example:

1. Open all issues. Scroll to page 3.
2. Start applying filters by clicking on values in columns (for example, Milestone, Assignee, Priority).
3. If your filtered list no longer has 3 pages, you will get a 404 error. You can fix it by changing the URL to "page=1".

For example, in my tracker it tries to load this URL: https://bitbucket.org/dilerlms/diler-digital-learning-environment/issues?status=new&status=open&page=2&milestone=5.0.2

This gives a 404 error. If I instead use this URL: https://bitbucket.org/dilerlms/diler-digital-learning-environment/issues?status=new&status=open&page=1&milestone=5.0.2

it is OK. I think the simplest fix is to always go back to page=1 when a new filter is applied.