Fixed the pcase branches for tp-palette-bg-p and tp-palette-fbg-p
predicates which had an extra `symbol` keyword incorrectly placed
between the pattern and the return expression. This caused these
branches to return the original symbol instead of the processed
intern result, leading to tp-palette settings not taking effect
when using palettes with -bg or -fbg suffixes.
Co-authored-by: Kinneyzhang <38454496+Kinneyzhang@users.noreply.github.com>
