Use Spider timeout for Browserker's crawl timeout setting

What does this MR do and why?

• Use the existing spider timeout DAST Scanner Profile setting to populate the value for DAST_BROWSER_CRAWL_TIMEOUT, a variable used exclusively by Browser Based DAST.
• Replaces "Spider Timeout" with "Crawler Timeout" in copies.

Relevant Issue: #430208 (closed)

Screenshots or screen recordings

backend

frontend

Before

After

How to set up and validate locally

1. Start GitLab using the GDK
2. Go to any project's "Security Configuration" under the "Secure" menu
3. Scroll to "DAST Profiles" and click "Manage Profiles"
4. Either add a new profile or edit an existing one

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #430208 (closed)