[BUG] File-to-field-aliases UI handling is incorrect for external node drivers

[fujitsu-domzalskis]

Setup

• Rancher version: 2.13.2
• Rancher UI Extensions: n/a
• Browser type & version: Microsoft Edge v146.0.3856.84

Describe the bug
Using annotation nodedriver.cattle.io/file-to-field-aliases in external node drivers (tested specifically on https://github.com/fujitsu/docker-machine-driver-fsas) automatically adds multiline UI annotation io.cattle.nodedriver/ui-field-hints: '{"userdata":{"type":"multiline"}}' but input field remains one-line string field. Also "\n" is not interpreted as newline character.

To Reproduce

1. Import external node driver which uses annotation nodedriver.cattle.io/file-to-field-aliases.
2. Navigate to Cluster Management > Create > Imported Node Driver ("fsas" in tested scenario).
3. Create dummy cloud credentials.
4. Navigate to Machine Pools > userdata parameter.
5. Try to insert there multiline YAML file with custom userdata.

Result

New line character is ignored.

Expected Result
Multiline input field which allows inserting YAML files or possibility to upload a file instead of text input.

Screenshots
Import of external node driver on "local" cluster:

YAML of node driver resource after it was important - ui field hint automatically added:

Dummy cloud credentials:

Attempt to insert multiline input to "userdata" field (typed "test" + Enter + Shift&Enter + "test"):

Element inspect:

Additional context
We confirmed that the kubectl patch command from the PR Replaces hardcoded schema-driver field mappings with annotation-based configuration by apoorvajagtap · Pull Request #50520 · rancher/rancher worked correctly — custom userdata was applied alongside the generated one but this is not solution or even a workaround for users.

@richard-cox was notified about this issue via email before creating it.

[IsaSih]

In generic.test.ts, there is no test for "multiline" type being passed through typeForField in cloud credential generic.
The INPUT_TYPES in generic.vue (cloud credential) only includes ['number', 'password', 'text']. Issue #17065 centers on "multiline" support, but that's only tested in the machine config component. The cloud credential test doesn't verify that multiline is not accidentally handled. Could you please, include this scenario?

[IsaSih]

Manual test required.