Resolved issue: https://github.com/usebruno/bruno/issues/4672 (#5900)

- Added interpolation to setVar method's value field.
- Added playwright test to test the fix.
- Added jest test to test out the fix.

---
Playwright - PASS
Jest - PASS
---

tests/interpolation/dynamic-variable/collection/set-var-dynamic-variable.bru

@@ -0,0 +1,25 @@
+meta {
+  name: set-var-dynamic-variable
+  type: http
+  seq: 1
+}
+
+post {
+  url:  https://echo.usebruno.com
+  body: json
+  auth: none
+}
+
+headers {
+  Content-Type: application/json
+}
+
+script:pre-request {
+  bru.setVar("title", "{{$randomFirstName}}");
+}
+
+body:json {
+  {
+    "title": "{{title}}"
+  }
+}