collab: Remove CountLanguageModelTokens RPC message (#29314)

This PR removes the `CountLanguageModelTokens` RPC message from collab.

We were only using this for Google AI models through the Zed provider
(which is only available to Zed staff).

For now we're returning `0`, but will bring back soon.

Release Notes:

- N/A

crates/proto/proto/ai.proto

@@ -172,19 +172,3 @@ enum LanguageModelRole {
     LanguageModelSystem = 2;
     reserved 3;
 }
-
-message CountLanguageModelTokens {
-    LanguageModelProvider provider = 1;
-    string request = 2;
-}
-
-message CountLanguageModelTokensResponse {
-    uint32 token_count = 1;
-}
-
-enum LanguageModelProvider {
-    Anthropic = 0;
-    OpenAI = 1;
-    Google = 2;
-    Zed = 3;
-}

crates/proto/proto/zed.proto

@@ -206,9 +206,6 @@ message Envelope {
         GetImplementation get_implementation = 162;
         GetImplementationResponse get_implementation_response = 163;
 
-        CountLanguageModelTokens count_language_model_tokens = 230;
-        CountLanguageModelTokensResponse count_language_model_tokens_response = 231;
-
         UpdateChannelMessage update_channel_message = 170;
         ChannelMessageUpdate channel_message_update = 171;
 
@@ -397,6 +394,7 @@ message Envelope {
     reserved 205 to 206;
     reserved 221;
     reserved 224 to 229;
+    reserved 230 to 231;
     reserved 246;
     reserved 270;
     reserved 247 to 254;

crates/proto/src/proto.rs

@@ -50,8 +50,6 @@ messages!(
     (CloseBuffer, Foreground),
     (Commit, Background),
     (CopyProjectEntry, Foreground),
-    (CountLanguageModelTokens, Background),
-    (CountLanguageModelTokensResponse, Background),
     (CreateBufferForPeer, Foreground),
     (CreateChannel, Foreground),
     (CreateChannelResponse, Foreground),
@@ -374,7 +372,6 @@ request_messages!(
     (PerformRename, PerformRenameResponse),
     (Ping, Ack),
     (PrepareRename, PrepareRenameResponse),
-    (CountLanguageModelTokens, CountLanguageModelTokensResponse),
     (RefreshInlayHints, Ack),
     (RefreshCodeLens, Ack),
     (RejoinChannelBuffers, RejoinChannelBuffersResponse),