Replace u/npc_has_var with compare_string

[GuardianDll]

Summary

None

Purpose of change

Got told that u/npc_has_var is on a chopping block, because it does the same thing as compare_string, but limited to only two scopes out of four
Well if it's on a chopping block, let's chop it

Describe the solution

Use regex to replace all uses of u/npc_has_var with compare_string
Fix manually the rest that was not hit with regex

Testing

TBD

Additional context

Regex used:

"npc_has_var": "([A-Za-z0-9_-]*)",[\n 	]* "value": "([A-Za-z0-9_-]*)"

"compare_string": [ "$2", { "npc_val": "$1" } ]

"u_has_var": "([A-Za-z0-9_-]*)",[\n 	]* "value": "([A-Za-z0-9_-]*)"

"compare_string": [ "$2", { "u_val": "$1" } ]

copy of #76006 without conflicts with #75392