VLC allows having custom variables in its --input-title-format parameter
value for displaying certain **stream metadata**, for example `$a` for
the stream author metadata or `$t` for the stream title metadata.

To avoid unintended variable substitution, `$` characters need to be
escaped by replacing `$` with `$$`.

https://wiki.videolan.org/Documentation:Format_String/

When Streamlink's --title argument was implemented in 5c3cf57,
a workaround was added for VLC, so users could escape a dollar sign
with a leading backslash in the --title value, so the resulting `\$$`
sequence would be turned back into a regular `$`, allowing VLC
to interpret stream metadata variables.

However, the title value that's passed to `PlayerOutput` is already
formatted by the CLI's `Formatter` instance, which means
that it can include arbitrary **plugin metadata**, like stream IDs,
author names, category names, stream titles, etc.

This means that if the user has for example set `--title` to `{title}`
and the plugin's `title` metadata includes the `\$` sequence, then
this will be turned into a single `$` character, making VLC interpret
it and its following character as a stream metadata variable.

Fix this by removing the flawed dollar sign escape logic.