Display selected and validated image filename in the 'Edit Image' box

Currently, if an image was selected from Image Gallery and the choice was validated, the user doesn't know which image is editing in 'Edit Image' modal, since the name of the image chosen is not displayed anywhere.

Before implementing XWIKI-19965, the single way to see if the image selected (and edited) was the correct (desired) one was to click 'Change Image', which led the user to the Gallery, where the respective image was highlighted when was clicked on it.

Now, if the image is validated by double-clicking, when the user returns to Gallery using 'Change Image' button, no image is highlighted, so it cannot be known for sure which image was previously selected and validated to edit mode (unless inserting it in the page to be visualized).