Use different display name for anthropic/claude-2

[mkondratek]

Fixes #630.

Test plan

1. try chat on a pro account

[kalanchan]

approving to get this out into the next build.

@mkondratek Could you explain how a user would even select Claude 2 if it's not part of the LLM dropdown?

[mkondratek]

approving to get this out into the next build.

@mkondratek Could you explain how a user would even select Claude 2 if it's not part of the LLM dropdown?

On sendMessege, in the beginning of the method's body we take the chosen model with this method:

private fun fetchModelFromDropdown(): ChatModel {
    return if (chatPanel.modelDropdown.selectedItem != null) {
      val selectedItem = chatPanel.modelDropdown.selectedItem
      val displayModelName = (selectedItem as CodyModelComboboxItem).name
      ChatModel.fromDisplayName(displayModelName) // <- HERE
    } else {
      ChatModel.UNKNOWN_MODEL
    }
  }

enum class ChatModel(val icon: Icon, val displayName: String, val agentName: String) {
  UNKNOWN_MODEL(Icons.CodyLogo, "", ""),
  ANTHROPIC_CLAUDE_2(Icons.LLM.Anthropic, "Claude 2.0 by Anthropic", "anthropic/claude-2"), // <- the old code
  ANTHROPIC_CLAUDE_2_0(Icons.LLM.Anthropic, "Claude 2.0 by Anthropic", "anthropic/claude-2.0"),
  // ...
  
companion object {
    // ...
    fun fromDisplayName(displayName: String): ChatModel =
        ChatModel.values().firstOrNull { it.displayName == displayName } ?: UNKNOWN_MODEL
    // ...
  }
}  

The problem was that displayName that we are matching in ChatModel.fromDisplayName(displayModelName) is the same: "Claude 2.0 by Anthropic" for both models anthropic/claude-2 and anthropic/claude-2.0.

[mkondratek]

My solution is rather a quick fix only. We must rethink how we store the models (probably we should not use enums at all).