fix(actions): evaluate each ${{ }} part on its own (#38754)

Every `${{ }}` part was spliced as raw text into a synthesized
`format('...', <raw>)` call and re-parsed, so unbalanced parentheses
restructured the whole expression:

```yaml
run-name: ${{ 1) && (2 }}     # panicked, aborting workflow parsing for the push
if: x ${{ 1) && (2 }} y       # silently evaluated to 2
```

One scanner shaped like GitHub's template reader now splits every value
and each part is evaluated on its own, so nothing builds an expression
out of text. A part that fails is an error instead of an empty string,
making a `run-name`, `runs-on` or job name that GitHub rejects invalid
here too.

Replaces https://github.com/go-gitea/gitea/pull/38736 as the actual root-cause fix.
Signed-off-by: silverwind <me@silverwind.io>

modules/actions/jobparser/model.go

@@ -8,7 +8,6 @@ import (
 	"errors"
 	"fmt"
 
-	"gitea.com/gitea/runner/act/exprparser"
 	"gitea.com/gitea/runner/act/model"
 	"go.yaml.in/yaml/v4"
 )
@@ -526,15 +525,7 @@ func EvaluateJobIfExpression(jobID string, job *Job, gitCtx map[string]any, resu
 		}
 	}
 	evaluator := NewExpressionEvaluator(NewInterpeter(jobID, actJob, matrix, toGitContext(gitCtx), results, vars, inputs))
-	expr, err := rewriteSubExpression(job.If.Value, false)
-	if err != nil {
-		return false, err
-	}
-	result, err := evaluator.evaluate(expr, exprparser.DefaultStatusCheckSuccess)
-	if err != nil {
-		return false, err
-	}
-	return exprparser.IsTruthy(result), nil
+	return evaluator.evaluateCondition(job.If.Value)
 }
 
 // parseMappingNode parse a mapping node and preserve order.