Set proper runAfter variable in edit mode

What does this MR do?

The frontend currently sends the dastProfileUpdate mutation with a runAfterCreate variable, which is actually only meant for the dastProfileCreate mutation. To function properly, the mutation requires a runAfterUpdate variable instead.

How to test this?

1. Enable the feature flag.

echo "Feature.enable(:dast_saved_scans)" | rails c

2. If !53432 (merged) has been merged, rebase this branch against master. Otherwise, rebase against the philipcunningham-add-dast-profile-update-mutation-295244 branch.
3. Edit any of your previously created DAST Scans.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry (This feature is still behind a feature flag)
• [-] Documentation (if required)
• Code review guidelines
• [-] Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Related to #295242 (closed)