The bdev_allow_write_mounted=0 snippet is part of the kernel command line, meaning that it’s a setting the core of the OS interprets at boot time. The best way to remove the option is to use these instructions:
Specifically, you would want to boot into PERSISTENT Mode | SYSMAINT Session, and then write the following contents into a new file at /etc/default/grub.d/50_user.cfg:
GRUB_CMDLINE_LINUX="$(echo "$GRUB_CMDLINE_LINUX" | str_replace "bdev_allow_write_mounted=0" "")"
(Note that I just edited the linked documentation to include instructions on removing kernel parameters using this method.)
Once the settings are set, run update-grub, make sure you don’t get any error messages, then reboot. (Note that messing with boot options is always dangerous, so you might want to snapshot your VM before you do this.)