Improve online runner check (#35722)

This PR moves "no online runner" warning to the runs list. 

A job's `runs-on` may contain expressions like `runs-on: [self-hosted,
"${{ inputs.chosen-os }}"]` so the value of `runs-on` may be different
in each run. We cannot check it through the workflow file.

<details>
  <summary>Screenshots</summary>

Before:

<img width="960" alt="3d2a91746271d8b1f12c8f7d20eba550"
src="https://github.com/user-attachments/assets/7a972c50-db97-49d2-b12b-c1a439732a11"
/>

After:

<img width="960" alt="image"
src="https://github.com/user-attachments/assets/fc076e0e-bd08-4afe-99b9-c0eb0fd2c7e7"
/>
</details>

This PR also splits `prepareWorkflowDispatchTemplate` function into 2
functions:
- `prepareWorkflowTemplate` get and check all of the workflows
- `prepareWorkflowDispatchTemplate` only prepare workflow dispatch
config for `workflow_dispatch` workflows.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/actions/runner.go

@@ -14,6 +14,7 @@ import (
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/shared/types"
 	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/container"
 	"code.gitea.io/gitea/modules/optional"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/timeutil"
@@ -173,6 +174,13 @@ func (r *ActionRunner) GenerateToken() (err error) {
 	return err
 }
 
+// CanMatchLabels checks whether the runner's labels can match a job's "runs-on"
+// See https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-syntax#jobsjob_idruns-on
+func (r *ActionRunner) CanMatchLabels(jobRunsOn []string) bool {
+	runnerLabelSet := container.SetOf(r.AgentLabels...)
+	return runnerLabelSet.Contains(jobRunsOn...) // match all labels
+}
+
 func init() {
 	db.RegisterModel(&ActionRunner{})
 }