Fixing the milestone title in the Bug Prioritization report

What does this MR do and why?

Fixing the milestone title in the Bug Prioritization report and slack handle for test platforms

The default 20 fetches the milestone until 16.7 which is the current milestone. In the Bug prioritization reports generated recently the upcoming milestone title is not displayed because of this issue. There are total of 31 results for this api, and the last milestone available is 17.0. Given that we might populate more milestones in the near future, I have added the pagination to 100, which will ensure that the upcoming milestone is always fetched.

Related to !2422 (merged)

Action items

• If adding environment variables for reactive processors, update config/triage-web.yaml and .gitlab/ci/triage-web.yml
• (If applicable) Add documentation to the handbook pages for Triage Operations =>
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels =>
  • Engineering week-in-review