fix(types): path is required within incremental results (#3961)

extracted from #3960

thanks @benjie for pointing this out!

Author: yaacovCR

src/execution/IncrementalPublisher.ts

@@ -100,7 +100,7 @@ export interface IncrementalDeferResult<
 > {
   errors?: ReadonlyArray<GraphQLError>;
   data: TData;
-  path?: ReadonlyArray<string | number>;
+  path: ReadonlyArray<string | number>;
   extensions?: TExtensions;
 }
 
@@ -110,7 +110,7 @@ export interface FormattedIncrementalDeferResult<
 > {
   errors?: ReadonlyArray<GraphQLFormattedError>;
   data: TData;
-  path?: ReadonlyArray<string | number>;
+  path: ReadonlyArray<string | number>;
   extensions?: TExtensions;
 }
 
@@ -120,7 +120,7 @@ export interface IncrementalStreamResult<
 > {
   errors?: ReadonlyArray<GraphQLError>;
   items: TData;
-  path?: ReadonlyArray<string | number>;
+  path: ReadonlyArray<string | number>;
   extensions?: TExtensions;
 }
 
@@ -130,7 +130,7 @@ export interface FormattedIncrementalStreamResult<
 > {
   errors?: ReadonlyArray<GraphQLFormattedError>;
   items: TData;
-  path?: ReadonlyArray<string | number>;
+  path: ReadonlyArray<string | number>;
   extensions?: TExtensions;
 }