fix: Use default javascript.options.strict=false (#1357)
fix: Use default javascript.options.strict=false (#1357)

The `javascript.options.strict` option results in lots of log spam,
which not only makes debugging harder, but also slows down Firefox.

The `javascript.options.showInConsole` option was removed too because
true is already the default value.

Fixes #1355
mozilla/web-ext,mozilla/web-ext,kumar303/web-ext,rpl/web-ext,rpl/web-ext,kumar303/web-ext