Microsoft.Extensions.AI.OpenAI nuget package constrains OpenAI to <2.13.0

### Description

the version of the dependency is constrained, blocking us from updating that nuget package

... is that on purpose?

### Reproduction Steps

go to https://www.nuget.org/packages/Microsoft.Extensions.AI.OpenAI#dependencies-body-tab
observe that the dependency on the OpenAI package is constrained to be smaller than 2.13.0

### Expected behavior

no constraint

### Actual behavior

cannot update OpenAI nuget package, which is recommended by VS

### Regression?

_No response_

### Known Workarounds

_No response_

### Configuration

.net 10 sdk 10.0.401
VS 2026 september update, enterprise

### Other information

_No response_

Start by inspecting the Microsoft.Extensions.AI.OpenAI package dependency metadata and the project file that defines its OpenAI version. Verify why the dependency is constrained below 2.13.0, then update the constraint if unintended. Done means the NuGet package permits the recommended OpenAI version without blocking updates.

Written by the indexing model from the issue text.