Geo 2.0 Regression - Add ability to remove primary

What does this MR do?

Closes #338231 (closed)

This is the fix for a UI bug that came to be after our recent Geo redesign. In the UI a Primary node should be able to be removed if all the secondary nodes are first removed. However, the UI always disabled the ability to remove the primary node.

This change adds a getter to tell the components if they can/cannot remove a node.

Screenshots or Screencasts (strongly suggested)

Removing Nodes Removing Nodes

https://docs.gitlab.com/ee/administration/geo/replication/disable_geo.html#remove-the-primary-site-from-the-ui

Before	After

https://docs.gitlab.com/ee/administration/geo/replication/version_specific_updates.html

Before	After
N/A

How to setup and validate locally (strongly suggested)

1. Set up Geo on your GDK
2. Fetch/Checkout this branch on your Primary Node (gdk-primary)
3. Navigate to the Geo Nodes UI http://127.0.0.1:3000/admin/geo/nodes.
4. Ensure Primary node cannot be removed if secondaries exist
5. Ensure Secondary node(s) can be removed
6. Remove all secondary nodes
7. Ensure Primary node can now be removed

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.

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

Related to #338231 (closed)