Remove DAST scanned resources from MR Security Report

What does this MR do?

This addresses #330122 (comment 573094303)

• Remove scanned resources until we fix underline performance issue
• Allow users to download scanned resources

Related backend changes - !61221 (merged) (cc @craigmsmith)

Screenshots (strongly suggested)

dast_scanned_resources

How to test this

• This can easily verified on the review app
  • https://gitlab-review-djadmin-da-5otlhs.gitlab-review.app/root/dast-testing-imported/-/merge_requests/2
  • Note: Password for the review app is in the 1password vault
• To verify this locally, you need to setup a project with DAST vulnerabilities
  • A quick way is to import the project in the aforementioned review app
  • Create a MR (feature-branch targeting the master)
  • The MR security report will show the changes under "Download scanned resources"

Does this MR meet the acceptance criteria?

Conformity

• I have included a changelog entry, or it's not needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• I have tested this MR in all supported browsers, or it's not needed.
• I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.

Security

Does this MR contain changes to processing or storing of credentials or tokens, authorization and authentication methods or other items described in the security review guidelines? If not, then delete this Security section.

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team