fix(es/decorator): Fix type detection for template literal types (#6786)

**Related issue:**

 - Closes #6682.

crates/swc_ecma_transforms/tests/fixture/legacy-metadata/issues/6683/input.ts

@@ -0,0 +1,8 @@
+function decorator(): PropertyDecorator {
+    return () => null
+}
+
+class Example {
+    @decorator()
+    value?: `prefix${string}`;
+}

crates/swc_ecma_transforms/tests/fixture/legacy-metadata/issues/6683/output.ts

@@ -0,0 +1,10 @@
+function decorator(): PropertyDecorator {
+    return ()=>null;
+}
+class Example {
+    value?: `prefix${string}`;
+}
+__decorate([
+    decorator(),
+    __metadata("design:type", String)
+], Example.prototype, "value", void 0);

crates/swc_ecma_transforms_proposal/src/decorators/legacy/metadata.rs

@@ -511,7 +511,7 @@ fn get_type_ann_of_pat(p: &Pat) -> Option<&TsTypeAnn> {
 fn is_str(ty: &TsType) -> bool {
     match ty {
         TsType::TsLitType(TsLitType {
-            lit: TsLit::Str(..),
+            lit: TsLit::Str(..) | TsLit::Tpl(..),
             ..
         })
         | TsType::TsKeywordType(TsKeywordType {