ssh kitten fails when $KITTY_PUBLIC_KEY contains a backtick (`)

[morgan-greywolf]

When the value of $KITTY_PUBLIC_KEY contains a a backtick (`), and the remote server executes bootstrap.sh, the following error is printed and the shared remote connection drops:
: 8: /home/user/.kitty-ssh-kitten-untar-4wL3BHIP7aML/data.sh: Syntax error: Unterminated quoted stringre

the second line of /home/user/.kitty-ssh-kitten-untar-4wL3BHIP7aML/data.sh on the remote server ends up attempting to set KITTY_PUBLIC_KEY, but the backtick is not properly escaped for bash/dash.

This is the contents of data.sh:

export KITTY_PUBLICexport COLORTERM="truecolor"
export KITTY_PUBLIC_KEY="1:E$H(!Q5w-${iAV1ADIS{Bjb^7>N3qSZ~Ie2a5Q\`~"
export KITTY_REMOTE="if-needed"
export KITTY_SHELL_INTEGRATION="enabled"
export KITTY_SSH_KITTEN_DATA_DIR=".local/share/kitty-ssh-kitten"
export KITTY_WINDOW_ID="28"
export TERM="xterm-256color"
export WINDOWID="100663310"_KEY="1:E$H(!Q5w-${iAV1ADIS{Bjb^7>N3qSZ~Ie2a5Q\`~"
export KITTY_REMOTE="if-needed"
export KITTY_SHELL_INTEGRATION="enabled"
export KITTY_SSH_KITTEN_DATA_DIR=".local/share/kitty-ssh-kitten"
export KITTY_WINDOW_ID="28"
export TERM="xterm-256color"
export WINDOWID="100663310"```