Toggle VSA navigation with feature flag

What does this MR do?

This MR is part of the process to remove the vertical VSA navigation

Currently both the path (horizontal) navigation and vertical navigation are displayed if the value_stream_analytics_path_navigation feature flag is enabled.

NOTE: Additional feature specs for the path navigation will be added in !56437 (merged)

This MR:

• Ensures only a single navigation option is displayed
• Moves the path navigation out of the search box
• Moves the search bar above other filters
• Updates related specs

This MR requires !55572 (merged) which ensures the extended create / edit functionality is available from the path navigation.

Screenshots (strongly suggested)

Feature flag OFF	feature flag ON	Loading

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because it is behind disabled feature flags.
• 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

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• 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

Related to #277379 (closed)