Migrate On-demand scans to use Browser based DAST
## Problem
On-demand scans is only able to run a proxy-based DAST scan.
Support should be added to run a browser-based on-demand Scan in both non FIPS and FIPS modes.
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To ensure a simpler implementation, we will be performing a replacement of ZAP with Browserker instead of a choice driven phased rollout.
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Rollout can be initiated once the following issues are closed:
* [x] [**Modify DAST On Demand Scan CI Configuration to enable Browser Based Scan**](https://gitlab.com/gitlab-org/gitlab/-/issues/430191 "Modify DAST On Demand Scan CI Configuration to enable Browser Based Scan")
* [x] [**Map Spider Timeout Configuration to Crawl Timeout for Browser Based DAST On Demand Scans**](https://gitlab.com/gitlab-org/gitlab/-/issues/430208 "Map Spider Timeout Configuration to Crawl Timeout for Browser Based DAST On Demand Scans")
* [x] [**Change Scanner and Site Profile Configuration Pages for Browser Based On Demand DAST**](https://gitlab.com/gitlab-org/gitlab/-/issues/430210 "Change Scanner and Site Profile Configuration Pages for Browser Based On Demand DAST")
epic