Steps to reproduce:
1. Open the attached user's project "U.1472035.zip"
2. Open the "SampleScene.unity" and select the "Assets/brickTexture.png" texture
3. In the Inspector, set its Texture Shape to 2D. In the preview, the size is 170.7 KB (Image 1)
4. Now, change the Texture Shape to a 2D Array. Hit Apply
5. The size of the texture has doubled to 341.8 KB (Image 2)

Expected results: The size should be the same as there is only 1 texture in the 2D Array
Actual results: The size doubles when choosing a 2D Array

Reproducible on: 2020.3.45f1, 2021.3.19f1, 2022.2.7f1, 2023.1.0b5, 2023.2.0a4