The state of the Image Size lock ratio button is considered per editing session instead of per image

Steps to reproduce

1. Edit a page with CKEditor
2. Click on 'Image' from toolbar
3. Choose an image from the Gallery (or upload one)
4. Click 'Select' button
5. On 'Advanced' tab, click on Size lock ratio button to unlock it
6. Set a random Width and Height
7. Click 'Insert' button
8. On another line, insert a new image
9. In the Image dialog, go to 'Advanced' tab
10. Observe the state of the Size lock ratio button

Expected results

The Size lock ratio button is in locked state (the image dimensions are locked by default), as the image is new on the page and no Width and Height was inserted so far.

Actual results

The Size lock ratio button is in unlocked state, keeping its last state from the current page editing session.

At this point, if on this second image the lock ratio button is clicked to be locked and then go to first inserted image and double click on it, the button is in locked state, which is not quite true for the current situation, because the size ratio was unlocked for that image when the random Width and Height were set initially in relation to the image's original dimensions.