Update `LiveValidator.operationSearcher` to support path disambiguation.

[scbedd]

Still pending conformation from the RPaaS team, but Wendy is thinking the following. Waiting on confirmation from roopesh for the strategy.

RPaaS's payload to OAV

{
...
// Internal field to OAV and should not be included in the payload validation
"rpaasOavInternalMetadata": {
"providerNamespace": "Microsoft.Contoso.ServiceGroup1"
}
}

RP spec 1

/specification/contoso/resource-manager/Microsoft.Contoso/stable/2023-12-01/openapi.json

{
...
"info": {
"version": "2023-12-01",
"providerNamespace": "Microsoft.Contoso"
},
"paths": {
"/providers/Microsoft.Contoso/operations": {
...
}

RP spec 2

/specification/contoso/resource-manager/Microsoft.Contoso/employees/stable/2023-12-01/openapi.json

{
...
"info": {
"version": "2023-12-01",
"providerNamespace": "Microsoft.Contoso.ServiceGroup1"
},
"paths": {
"/providers/Microsoft.Contoso/operations": {
      "get": {
        "tags": [
              "Microsoft.Contoso.ServiceGroup1", "employees"
        ],
...
}