Label Studio SSRF on Import Bypassing `SSRF_PROTECTION_ENABLED` Protections

Label Studio is a popular open source data labeling tool. The vulnerability affects all versions of Label Studio prior to 1.11.0 and was tested on version 1.8.2. Label Studio's SSRF protections that can be enabled by setting the `SSRF_PROTECTION_ENABLED` environment variable can be bypassed to access internal web servers. This is because the current SSRF validation is done by executing a single DNS lookup to verify that the IP address is not in an excluded subnet range. This protection can be bypassed by either using HTTP redirection or performing a DNS rebinding attack.