Fix warnings for ValueHelp images

[finkmanAtSap]

Fixes the following runtime warnings:

Assets in public directory cannot be imported from JavaScript.
If you intend to import that asset, put the file in the src directory, and use /src/images/vhp-valuehelpdialog-single.jpg instead of /public/images/vhp-valuehelpdialog-single.jpg.
If you intend to use the URL of that asset, use /images/vhp-valuehelpdialog-single.jpg?url.
Assets in public directory cannot be imported from JavaScript.
If you intend to import that asset, put the file in the src directory, and use /src/images/vhp-valuehelpdialog-multi.jpg instead of /public/images/vhp-valuehelpdialog-multi.jpg.
If you intend to use the URL of that asset, use /images/vhp-valuehelpdialog-multi.jpg?url.
Files in the public directory are served at the root path.
Instead of /public/images/vhp-valuehelpdialog-single.jpg, use /images/vhp-valuehelpdialog-single.jpg.
Files in the public directory are served at the root path.
Instead of /public/images/vhp-valuehelpdialog-multi.jpg, use /images/vhp-valuehelpdialog-multi.jpg.