Increase maximum size of input buffer in ash

[illiliti]

Current limit is too small. Pasting large strings like urls results in truncation. Consider using 4096 or 8192 to fix this.

https://github.com/kisslinux/repo/blob/f9d57a2dca54ec42a3426988242d72424a894cda/core/busybox/files/.config#L101