How to reproduce:
1. Open the attached project "Test"
2. Open the "SampleScene" scene
3. Make sure to have the "Animator" tab opened and select the "Test1" GameObject in the Hierarchy
4. Select the transition between the "Test1" and "test1_2" animations
5. Click the "+" button to add a condition
6. In the Animator window, delete the parameter "test" and create another parameter
7. Select the Transition again and observe the Conditions tab
Expected results: The Conditions window shows only "Parameter does not exist in Controller"
Actual results: The Conditions window shows the empty dropdown and the warning at the same time
Reproducible with: 2022.3.58f1, 6000.0.40f1, 6000.1.0b8, 6000.2.0a5
Reproducible on: macOS Sequoia 15.3
Not reproducible on: No other environment tested
Note: When the only Parameter is deleted and another one is not added, the empty dropdown is not displayed