fix: when metadata has a newline playout stops (#3160)

### Description

If the title or artist metadata in libretime has a newline, that file is
not played as telnet takes the newline as a command enter in the middle
of the command.

**This is a new feature**:

No

**I have updated the documentation to reflect these changes**:

No

### Testing Notes

**What I did:**

I spun up a fresh local LibreTime instance, uploaded a track with a
newline in the creator field. I then created a show and added the track
to the show and verified that the track did not play with error:

```
playout-1  | 2025-06-06 17:41:49,888 | ERROR    | libretime_playout.liquidsoap.client._client:_set_var:50 - ERROR: unknown command, type "help" to get a list of commands.
```

I then added my fix and verified that the track did play as it was
supposed to.

**How you can replicate my testing:**

See the above section

---------

Co-authored-by: jo <ljonas@riseup.net>

playout/libretime_playout/player/liquidsoap.py

@@ -30,10 +30,12 @@ def create_liquidsoap_annotation(file_event: FileEvent) -> str:
     # the metadata we get from LibreTime. (You can modify metadata in LibreTime's library,
     # which doesn't get saved back to the file.)
     if file_event.artist_name:
-        annotations["artist"] = file_event.artist_name.replace('"', '\\"')
+        value = file_event.artist_name.replace('"', '\\"').strip().replace("\n", " ")
+        annotations["artist"] = value
 
     if file_event.track_title:
-        annotations["title"] = file_event.track_title.replace('"', '\\"')
+        value = file_event.track_title.replace('"', '\\"').strip().replace("\n", " ")
+        annotations["title"] = value
 
     annotations_str = ",".join(f'{key}="{value}"' for key, value in annotations.items())
 

playout/tests/player/liquidsoap_test.py

@@ -44,6 +44,24 @@ def test_create_liquidsoap_annotation():
         ":/fake/2.flac"
     )
 
+    file_event.artist_name = "New\nline to space"
+    file_event.track_title = "Trailing\nnewline\n"
+
+    assert create_liquidsoap_annotation(file_event) == (
+        "annotate:"
+        'media_id="2",'
+        'schedule_table_id="1",'
+        'liq_start_next="0",'
+        'liq_fade_in="0.5",'
+        'liq_fade_out="0.5",'
+        'liq_cue_in="13.7008",'
+        'liq_cue_out="315.845",'
+        'replay_gain="11.46 dB",'
+        'artist="New line to space",'
+        'title="Trailing newline"'
+        ":/fake/2.flac"
+    )
+
 
 def test_liquidsoap():
     Liquidsoap(MagicMock())