Remove securityScansSucceeded from DevOps Adoption

What does this MR do?

The securityScansSucceeded query was causing a timeout error. Also, it is effectively being replaced with queries for individual scan types. This removes the column from the DevOps adoption table in the UI, and sets the value to always be false in the SnapshotCalculator (some value is necessary because the database column is NOT NULL). This does not remove the database column, because this is an urgent change, so that column (and remaining code) will be removed in a follow-up issue.

Note: We already tried to fix the timeout problem. We also considered rescuing query timeouts, but decided it would be better to simply remove the feature.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• I have included changelog trailers, or none are 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.
• This change is backwards compatible across updates, or this does not apply.

Related to #335190 (closed)