Admin-configurable default protocol for path calculation

NetBrain currently applies a fixed default protocol (IPv4 with UDP/TCP) for path calculation, and this default applies uniformly to all users without any administrative control over it. This can produce results that are misleading when a policy match is evaluated against a protocol that does not reflect the traffic type the user actually intends to analyze. This enhancement would allow administrators to configure the default protocol and port used for path calculation, such as ICMP or TCP on port 443, so that the system-wide default better reflects common troubleshooting scenarios. Customers would gain more accurate and predictable path calculation results out of the box, reducing confusion around policy match outcomes and the need for users to manually adjust protocol settings on each path calculation.