SG-41669: Make buttons display text instead of missing icons

[chenlj1]

SG-41669: [RV] A-Z Sort buttons in Inputs section of Session Manager are not displaying the proper icons

Summarize your change.

Changed the code such that the buttons now use text to display "A-Z" and "Z-A" instead of using the missing sortup_48x48.png and sortdown_48x48.png.

Describe the reason for the change.

Previously, these two buttons were trying to display the two missing .png files for their icons. This caused the app to fall back to the default value for the buttons when the icons could not be found resulting in the two buttons displaying "..." instead of the expected value.

Describe what you have tested and on which operating system.

Tested on macOS to see if the buttons are now displaying the correct text instead of "..."

If possible, provide screenshots.

Buttons now show the "A-Z" and "Z-A" instead of "..."

[chenlj1]

I also went to check if any additional icons were missing. It looks like these were the only two icons that were missing. Everything else appears to be here.

[bernie-laberge]

I also went to check if any additional icons were missing. It looks like these were the only two icons that were missing. Everything else appears to be here.

Thanks for checking @chenlj1 !
By the way, as I discussed with Ling, it looks like this is a change in behaviour in Qt6 with missing image files associated with QToolButtons

[bernie-laberge]

Thank you @chenlj1 !