DOCSP-41778 query size limit (#3355)

## Pull Request Info

Jira ticket: https://jira.mongodb.org/browse/DOCSP-41778

- [C++/Sync Data/Manage Sync
Subscriptions](https://preview-mongodbosharafmdb.gatsbyjs.io/realm/DOCSP-41778-query-size-limit/sdk/cpp/sync/sync-subscriptions/#manage-your-subscriptions)
- [Flutter/Sync Device Data/Manage
Subscriptions](https://preview-mongodbosharafmdb.gatsbyjs.io/realm/DOCSP-41778-query-size-limit/sdk/flutter/sync/manage-sync-subscriptions/#query-size-limit)
- [Java/Sync Data/Mange Flexible Sync
Subscriptions](https://preview-mongodbosharafmdb.gatsbyjs.io/realm/DOCSP-41778-query-size-limit/sdk/java/sync/flexible-sync/#query-size-limit)
- [Kotlin/Sync Device Data/Manage
Subscriptions](https://preview-mongodbosharafmdb.gatsbyjs.io/realm/DOCSP-41778-query-size-limit/sdk/kotlin/sync/subscribe/#query-size-limit)
- [.NET/Sync Data/Manage Flexible Sync
Subscriptions](https://preview-mongodbosharafmdb.gatsbyjs.io/realm/DOCSP-41778-query-size-limit/sdk/dotnet/sync/flexible-sync/#query-size-limit)
- [Node.js//Sync Data/Manage Flexible Sync
Subscriptions](https://preview-mongodbosharafmdb.gatsbyjs.io/realm/DOCSP-41778-query-size-limit/sdk/node/sync/flexible-sync/#query-size-limit)
- [Swift//Sync Data/Manage Flexible Sync
Subscriptions](https://preview-mongodbosharafmdb.gatsbyjs.io/realm/DOCSP-41778-query-size-limit/sdk/node/sync/flexible-sync/#query-size-limit)

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### Release Notes

<!--
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Follow ToC strictly
- **Define Data Access Permissions**
- Data Access Role Examples: Update CRUD Permissions example screenshots
and
    copyable JSON
-->

- C++ SDK
- Sync Data/Manage Sync Subscriptions: Add a warning about the query
size limit when using Device Sync.

- Throughout the SDK Docs: Update the "Flexible Sync RQL Requirements
and Limitations" section to include the query size limit when using
Device Sync.

### Review Guidelines


[REVIEWING.md](https://github.com/mongodb/docs-app-services/blob/master/REVIEWING.md)

Author: osharaf-mdb

source/includes/flex-sync-limitations.rst

@@ -105,3 +105,9 @@ Embedded or Linked Objects
 
 Flexible Sync does not support querying on properties in Embedded Objects 
 or links. For example, ``obj1.field == "foo"``.
+
+Query Size Limit
+~~~~~~~~~~~~~~~~
+
+The **size limit** for any given query subscription in your subscription set is **256 kB**.
+Exceeding this limit results in a :ref:`LimitsExceeded Error<flexible-sync-errors>`. 

source/sdk/cpp/sync/sync-subscriptions.txt

@@ -82,6 +82,11 @@ The Realm C++ SDK also has a :cpp-sdk:`mutable_sync_subscription_set
 <structrealm_1_1mutable__sync__subscription__set.html>` that enables you to
 add, change, and remove ``sync_subscription`` objects.
 
+.. warning:: Query Size Limit
+
+   The **size limit** for any given query subscription in your subscription set is **256 kB**.
+   Exceeding this limit results in a :ref:`LimitsExceeded Error<flexible-sync-errors>`.
+
 .. _cpp-verify-subscription-size-find-subscription:
 
 Verify Number of Subscriptions or Find a Specific Subscription