Fixed: Fully consume unknown CSI sequences containing unsupported parameter and intermediate bytes

Standard ECMA-48: Control Functions for Coded Character Sets specifies the format of CSI commands.
- https://en.wikipedia.org/wiki/ANSI_escape_code#Control_Sequence_Introducer_commands
- https://invisible-island.net/xterm/ecma-48-parameter-format.html#section5.4

Previously unsupported bytes would be echoed to the terminal.

```shell
$ printf '\x1b[=u' # PF
u
$ printf '\x1b[=5u' # PPF
5u
$ printf '\x1b[=5!u' # PPIF
5!u
$ printf '\x1b[=5!%u' # PPIIF
5!0
$ printf '\x1b[=?5!%u' # PPPIIF
?5!0
```

This fixes a problem with fish shell 4.0.0 which uses that sequence.

Closes #4338

Co-authored-by: @krobelus <aclopte@gmail.com>
Co-authored-by: @agnostic-apollo  <agnosticapollo@gmail.com>