Ignore events other than play

All events in gPodder are :
- play
- download
- delete
- new
- flattr
(see https://gpoddernet.readthedocs.io/en/latest/api/reference/events.html)

`download` and `delete` are ignored by AntennaPod and cause issues with some frontends (see AntennaPod/AntennaPod#6957 (comment))

For `new`, the official documentaion says "This state needs to be interpreted by receiving clients and does not delete any information on the webservice." However, gpodder-sync will erase position and total if client put some value in it (-1 most of the time). It does not respect the spec and should be ignored as well.

`flattr` is undocumented and seems unused.

By elimination, only play is really helpfull.
We should not remove the action column because it can have NEW, DOWNLOAD and DELETE action already with -1 data and could cause damage if removed.

Author: Xefir

lib/Controller/EpisodeActionController.php

@@ -41,6 +41,7 @@ public function __construct(
 	public function create(): JSONResponse {
 
 		$episodeActionsArray = $this->filterEpisodesFromRequestParams($this->request->getParams());
+		$episodeActionsArray = $this->filterOnlyPlays($episodeActionsArray);
 		$this->episodeActionSaver->saveEpisodeActions($episodeActionsArray, $this->userId);
 
 		return new JSONResponse(["timestamp" => time()]);
@@ -74,4 +75,12 @@ public function list(int $since = 0): JSONResponse {
 	public function filterEpisodesFromRequestParams(array $data): array {
 		return array_filter($data, "is_numeric", ARRAY_FILTER_USE_KEY);
 	}
+
+	/**
+	 * @param array $data
+	 * @return array $episodeActionsArray
+	 */
+	public function filterOnlyPlays(array $data): array {
+		return array_filter($data, fn($ep) => isset($ep['action']) && strtolower($ep['action']) === 'play');
+	}
 }