query_main.cc: IsBefore(BoundPosition) -> IsInclusive(BoundPosition)

This fixes several test failures due to incorrect handling of startAfter and endBefore resulting from a change in core::Bound from "before" to "inclusive" in firebase/firebase-ios-sdk#9519

Namely, this fixes the following failure:
```
cursor_test.cc:250: Failure
Expected equality of these values:
  std::vector<std::string>({"c", "f", "b", "e"})
    Which is: { "c", "f", "b", "e" }
  QuerySnapshotToIds(snapshot)
    Which is: { "c", "f" }
[  FAILED  ] FirestoreIntegrationTest.TimestampsCanBePassedToQueriesAsLimits
```

e.g. https://github.com/firebase/firebase-cpp-sdk/runs/6044737005

Author: dconeybe

firestore/src/main/query_main.cc

@@ -227,7 +227,7 @@ core::Bound QueryInternal::ToBound(
     components->values[i] = *DeepClone(*value).release();
   }
 
-  return core::Bound::FromValue(std::move(components), IsBefore(bound_pos));
+  return core::Bound::FromValue(std::move(components), IsInclusive(bound_pos));
 }
 
 core::Bound QueryInternal::ToBound(
@@ -261,7 +261,7 @@ core::Bound QueryInternal::ToBound(
     }
   }
 
-  return core::Bound::FromValue(std::move(components), IsBefore(bound_pos));
+  return core::Bound::FromValue(std::move(components), IsInclusive(bound_pos));
 }
 
 Message<google_firestore_v1_Value> QueryInternal::ConvertDocumentId(
@@ -327,14 +327,14 @@ api::Query QueryInternal::CreateQueryWithBound(BoundPosition bound_pos,
   FIRESTORE_UNREACHABLE();
 }
 
-bool QueryInternal::IsBefore(BoundPosition bound_pos) {
+bool QueryInternal::IsInclusive(BoundPosition bound_pos) {
   switch (bound_pos) {
     case BoundPosition::kStartAt:
-    case BoundPosition::kEndBefore:
+    case BoundPosition::kEndAt:
       return true;
 
     case BoundPosition::kStartAfter:
-    case BoundPosition::kEndAt:
+    case BoundPosition::kEndBefore:
       return false;
   }
 

firestore/src/main/query_main.h

@@ -201,7 +201,7 @@ class QueryInternal {
       const nanopb::Message<google_firestore_v1_Value>& from,
       const core::Query& internal_query) const;
 
-  static bool IsBefore(BoundPosition bound_pos);
+  static bool IsInclusive(BoundPosition bound_pos);
 
   core::Bound ToBound(BoundPosition bound_pos,
                       const DocumentSnapshot& public_snapshot) const;