assistant: Add Mistral support (#24879)

Closes #12519.

Release Notes:

- Added support for Mistral to the Assistant.

---------

Co-authored-by: Marshall Bowers <git@maxdeviant.com>

Cargo.lock

@@ -6965,6 +6965,7 @@ dependencies = [
  "image",
  "lmstudio",
  "log",
+ "mistral",
  "ollama",
  "open_ai",
  "parking_lot",
@@ -7012,6 +7013,7 @@ dependencies = [
  "language_model",
  "lmstudio",
  "menu",
+ "mistral",
  "ollama",
  "open_ai",
  "project",
@@ -7973,6 +7975,19 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "mistral"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "futures 0.3.31",
+ "http_client",
+ "schemars",
+ "serde",
+ "serde_json",
+ "strum",
+]
+
 [[package]]
 name = "msvc_spectre_libs"
 version = "0.1.2"