Always allow `Connect` to `ManagedControlPlane`

[GenosseOtt]

Description

We want to provide the most useful, intuitive user experience to our end users.
We added a logic to prevent end users to ManagedControlPlanes that are not ready (e.g. when newly created, but API server or underlying infra still in creation)

Our definition of not ready, is not sophisticated and causes frustration on the user side as the instance of MCP is considered "Not ready", anytime it is changed.

Let's improve! Especially if I broke a provider (think: typo), its particularly frusttrating to be locked out of this page.

Acceptance Criteria

• Gray out Connect button when MCP is still creating (No Running API + Authentication + Authorization)
• Gray out if MCP cannot be connected to (Neither Running API + Authentication + Authorization)
• Do not gray out if MCP can be connected to, even though its status is Not Ready (Running API + Authentication + Authorization)
• Improve MCP Detail Screen (chances are higher this might return a 404 (MCP or any of the worload/content) or other error)

Out of scope

• Improve status messages on MCP side, but share this trouble with team (@n3rdc4ptn @ValentinGerlach @Diaphteiros)

[andreaskienle]

Here’s a related backlog item about giving users better feedback when their IdP setup isn’t supported: #143

See also: #137

[n3rdc4ptn]

This is a duplicate #137
I will close issue #137.