Some `toStream` implementations change the state of `std::ostream`

As discussed in https://github.com/acts-project/acts/pull/2814#discussion_r1551784177 there are some `toStream` and `<<` implementations which change the state of the stream without restoring it to its original state.

One solution to this would be to work with strings which then get written to the stream. Another to restore the stream to its original state. Yet another one not to change the state and customize the preferred output format before calling `toStream`.

CC @krasznaa as he discovered this