Steps to reproduce:
1. Open the attached project user's project "project.zip" on 6000.2.0b2 (2bdac9ac0d74)
2. Open the Editor.log
3. Search for:
"Refreshing native plugins compatible for Editor in 1.12 ms, found 1 plugins.
Preloading 1 native plugins for Editor in 23.90 ms."
4. Open the same project on 6000.3.0a1 (4592b02ab560)
5. Search for:
Refreshing native plugins compatible for Editor in 0.09 ms, found 0 plugins.
Preloading 0 native plugins for Editor in 0.00 ms.

Actual result: graphics plugin is not loaded on Editor initialization if installed via Package Manager
Expected result: graphics plugin is loaded on Editor initialization if loaded via Package Manager

Reproducible with: 6000.0.52f1, 6000.0.68f1, 6000.3.0a1 (4592b02ab560), 6000.3.9f1, 6000.4.0b9, 6000.5.0a7
Not reproducible with: 2022.3.71f1, 6000.0.51f1, 6000.2.0b2 (2bdac9ac0d74)

Environment tested: Windows 11 24H2

Notes:
-Plugin source is attached as "GraphicsPlugin.zip"
-This can be worked around by either the Package installing the plugin into Assets/Plugins or bypassing the Package Manager completely