Add support for Claude 3.5 Sonnet (#13371)

Release Notes:

- Added support for Claude 3.5 Sonnet.

crates/assistant/src/completion_provider/cloud.rs

@@ -101,7 +101,10 @@ impl CloudCompletionProvider {
                 count_open_ai_tokens(request, cx.background_executor())
             }
             LanguageModel::Cloud(
-                CloudModel::Claude3Opus | CloudModel::Claude3Sonnet | CloudModel::Claude3Haiku,
+                CloudModel::Claude3_5Sonnet
+                | CloudModel::Claude3Opus
+                | CloudModel::Claude3Sonnet
+                | CloudModel::Claude3Haiku,
             ) => {
                 // Can't find a tokenizer for Claude 3, so for now just use the same as OpenAI's as an approximation.
                 count_open_ai_tokens(request, cx.background_executor())

crates/assistant/src/completion_provider/open_ai.rs

@@ -210,6 +210,7 @@ pub fn count_open_ai_tokens(
 
             match request.model {
                 LanguageModel::Anthropic(_)
+                | LanguageModel::Cloud(CloudModel::Claude3_5Sonnet)
                 | LanguageModel::Cloud(CloudModel::Claude3Opus)
                 | LanguageModel::Cloud(CloudModel::Claude3Sonnet)
                 | LanguageModel::Cloud(CloudModel::Claude3Haiku) => {