fix(actions): keep github.event.inputs as strings for workflow_dispatch (#38899)

`github.event.inputs` must mirror the raw `workflow_dispatch` payload,
where
GitHub keeps every input as a string. Only the separate `inputs` context
preserves declared types, e.g. booleans. A previous fix coerced boolean
inputs in the single map that fed both contexts, so
`github.event.inputs.someBool` became a real boolean and comparisons
like
`== 'true'` stopped matching.

`github.event.inputs` now stays string-only again. The `inputs` context
used
for server-side `if:` evaluation of needs-gated/matrix-deferred jobs
re-coerces booleans independently, from the job's own workflow
declaration,
so that path keeps working correctly.

Fixes https://github.com/go-gitea/gitea/issues/38896

---------

Co-authored-by: Zettat123 <zettat123@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>

templates/repo/actions/workflow_dispatch_inputs.tmpl

@@ -19,7 +19,7 @@
 				</select>
 			{{else if eq .Type "boolean"}}
 				<label class="tw-flex flex-text-inline">
-					<input type="checkbox" name="{{.Name}}" {{if eq .Default "true"}}checked{{end}}>
+					<input type="checkbox" name="{{.Name}}" {{if .IsDefaultTrue}}checked{{end}}>
 					{{or .Description .Name}}
 				</label>
 			{{else if eq .Type "number"}}