[v2.9] Add "v26.0.x" option for "Docker Install URL" dropdown for RKE1

[chiukapoor]

Is your feature request related to a problem? Please describe.
As part of rancher/rancher#45013 we're adding support for Docker 26.0.x.

Describe the solution you'd like
UI dropdowns that allow picking "Docker Install URL" (e.g. on Node Template details page - not sure where else it may be referenced) should additional have "v26.0 (Recommended)" choice that populates https://releases.rancher.com/install-docker/26.0.sh when selected.

Describe alternatives you've considered
Note "Docker Install URL" is editable and doesn't limit users to only the choices available, so they can specify https://releases.rancher.com/install-docker/26.0.sh manually as well before this enhancement is done.
Consequently existing option "v25.0.x (Recommended)" should be changed to "v25.0.x".

Additional Information

When a new version of the docker install is published, the UI will fetch that version and mark it as the default. Our role usually involves adding the previous version to the hard-coded list to serve as a cache.

See rancher/ui#5045 and rancher/ui#5136 for examples of how this has been previously handled.

[richard-cox]

@chiukapoor is this for 2.9.0, or afterwards?

[richard-cox]

Similar to #10806

[chiukapoor]

@chiukapoor is this for 2.9.0, or afterwards?

Yes, This is for v2.9.

[chiukapoor]

Note: It needs to be handled only after backend changes are in.

[rak-phillip]

@richard-cox @chiukapoor does this need to be represented in v2.8-next1 as well?

[chiukapoor]

@richard-cox @chiukapoor does this need to be represented in v2.8-next1 as well?

No, this is only for v2.9

[mitulshah-suse]

@richard-cox backend related work is completed. It is not blocked on backed anymore.

[IsaSih]

test pass on v2.9-16190ecee0aa3fb4aa570aa0fc932a36d9dcd082-head