Remove API references to searching snippet blobs

What does this MR do?

Removes snippet blob searching references from the API

Relates to #208882 (closed)

Does this MR meet the acceptance criteria?

Because this is mostly a docs/developer-facing change, I've not added a changelog entry

Conformity

• Changelog entry
• 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.