language_models: Add vision support for OpenAI gpt-5, gpt-5-mini, and gpt-5-nano models (#36047)

## Summary
Enable image processing capabilities for GPT-5 series models by updating
the `supports_images()` method.

## Changes
- Add vision support for `gpt-5`, `gpt-5-mini`, and `gpt-5-nano` models
- Update `supports_images()` method in
`crates/language_models/src/provider/open_ai.rs`

## Models with Vision Support (after this PR)
- gpt-4o
- gpt-4o-mini
- gpt-4.1
- gpt-4.1-mini
- gpt-4.1-nano
- gpt-5 (new)
- gpt-5-mini (new)
- gpt-5-nano (new)
- o1
- o3
- o4-mini

This brings GPT-5 vision capabilities in line with other OpenAI models
that support image processing.

Release Notes:

- Added vision support for OpenAI models

crates/language_models/src/provider/open_ai.rs

@@ -301,7 +301,25 @@ impl LanguageModel for OpenAiLanguageModel {
     }
 
     fn supports_images(&self) -> bool {
-        false
+        use open_ai::Model;
+        match &self.model {
+            Model::FourOmni
+            | Model::FourOmniMini
+            | Model::FourPointOne
+            | Model::FourPointOneMini
+            | Model::FourPointOneNano
+            | Model::Five
+            | Model::FiveMini
+            | Model::FiveNano
+            | Model::O1
+            | Model::O3
+            | Model::O4Mini => true,
+            Model::ThreePointFiveTurbo
+            | Model::Four
+            | Model::FourTurbo
+            | Model::O3Mini
+            | Model::Custom { .. } => false,
+        }
     }
 
     fn supports_tool_choice(&self, choice: LanguageModelToolChoice) -> bool {