Updating all locations where DIRECTION was used instead of DECORATION

[dzaro-dev]

As per @MrD-RC 's feedback in PR#10031, I've updated all the locations where either

SYM_AH_DIRECTION_UP or SYM_AH_DIRECTION_DOWN were used to:

SYM_AH_DECORATION_UP and SYM_AH_DECORATION_UP.

I closed all the other PR's because this should be all under one PR and not separate ones.

This matches what is written in the the INAV Character Map.md and ensures that what is written there is also in the firmware code.

This also allowed the enabling of the direction scrolling arrows in displayport_msp_bf_compat.c when using DJI O3, as symbols are available to replace those blanks.

Hope this helps.