[BUG] Wrong format inside "formattime" results in the whole program being unusable

[RQuarx]

Checklist before submitting an issue

• I have searched through the existing closed and open issues for eww and made sure this is not a duplicate
• I have specifically verified that this bug is not a common user error
• I am providing as much relevant information as I am able to in this bug report (Minimal config to reproduce the issue for example, if applicable)

Description of the bug

Inserting any other characters that is not the format specifier of the formattime would result in the whole program being unusable / needing a full restart to wrok

Reproducing the issue

formattime(EWW_TIME, "%EWW")

Expected behaviour

EWW would stop responding to everything until the formattime is fixed, and a bunch of errors were spit out on the log

Additional context

Platform and environment

• compositor: Hyprland (Wayland)
• distro: ArchLinux
• eww_version: 0.5.0 d87c2fd