IO-100 Add is_sessioned flag to Function and FunctionData protos (#53711)

GitOrigin-RevId: f7c14ba92d699102d1010962c4f8d8606a0a743c

Author: KartikYZ

go/proto/modal_proto/api.pb.go

@@ -2035,6 +2035,9 @@ message Function {
   bool is_server = 92; // When True, the function is a server function
 
   string routing_region = 93; // Where inputs to a function should be routed through.
+
+  // True when the function is a Sessioned Server. Only valid together with is_server.
+  bool is_sessioned = 95;
 }
 
 message FunctionAsyncInvokeRequest {
@@ -2240,6 +2243,9 @@ message FunctionData {
   bool is_server = 41; // When True, the function is a server function
 
   string routing_region = 42; // Where inputs to a function should be routed through.
+
+  // True when the function is a Sessioned Server. Only valid together with is_server.
+  bool is_sessioned = 44;
 }
 
 message FunctionExtended {

modal_proto/api.proto

@@ -1110,6 +1110,7 @@ async def _load(self: _Function, resolver: Resolver, load_context: LoadContext,
                         http_config=http_config,
                         is_server=function_definition.is_server,
                         routing_region=function_definition.routing_region,
+                        is_sessioned=function_definition.is_sessioned,
                     )
 
                     ranked_functions = []