DCSW: Cannot use brackets around fleet vars in LocURIs

[JordanMontgomery]

Fleet version: 4.77 RC

Web browser and operating system:

---

💥  Actual behavior

I tried to use curly brackets around FLEET_VAR_SCEP_WINDOWS_CERTIFICATE_ID i.e. ${FLEET_VAR_SCEP_WINDOWS_CERTIFICATE_ID} and the LocURIs failed validation. We allow this format in other places variables are used so we should allow it in LocURIs

🛠️ To fix

Fix validation to allow brackets around variables

🧑‍💻  Steps to reproduce

1. Create a windows SCEP CSP XML profile but in the LocURIs use ${FLEET_VAR_SCEP_WINDOWS_CERTIFICATE_ID} instead of $FLEET_VAR_SCEP_WINDOWS_CERTIFICATE_ID
2. See that it fails to upload

🕯️ More info (optional)