[Typespec Authoring] remove client side limitation in azsdk_typespec_consult tool

Currently, the server side simply truncates the content when it exceeds the length limit. This raises a concern that the returned answer may be inaccurate because it is based on a truncated question. That is why we enforce a length limit on the tool side.
e.g.
https://github.com/Azure/azure-sdk-tools/blob/10cb315e39573016d79bfda3a0e813f2d7a3db01/tools/azsdk-cli/Azure.Sdk.Tools.Cli/Models/AzureSdkKnowledgeAICompletion/Message.cs#L23

We are considering enhancements on the backend side, where the service would return an error instead of automatically truncating the inputhttps://github.com/Azure/azure-sdk-pr/issues/2518.
Once the backend service is improved, we may remove the limitation enforced by the tool.