player/client: clear hooks when a client is destroyed

Clear any registered hook when a client is destroyed like it is already
done for OSD overlays and input sections. This is necessary both if a
client exists intentionally or by error. e.g. the script:

mp.add_hook("on_load", 0)
error()

logs the warning "Sending hook command failed. Removing hook." before
this commit.

player/client.c

@@ -457,6 +457,7 @@ static void mp_destroy_client(mpv_handle *ctx, bool terminate)
 
     osd_set_external_remove_owner(mpctx->osd, ctx);
     mp_input_remove_sections_by_owner(mpctx->input, ctx->name);
+    mp_remove_client_hooks(mpctx, ctx->id);
 
     mp_mutex_lock(&clients->lock);
 

player/command.c

@@ -184,6 +184,17 @@ static void hook_remove(struct MPContext *mpctx, struct hook_handler *h)
     MP_ASSERT_UNREACHABLE();
 }
 
+void mp_remove_client_hooks(struct MPContext *mpctx, int64_t client_id)
+{
+    struct command_ctx *cmd = mpctx->command_ctx;
+    for (int n = 0; n < cmd->num_hooks; n++) {
+        if (cmd->hooks[n]->client_id == client_id) {
+            talloc_free(cmd->hooks[n]);
+            MP_TARRAY_REMOVE_AT(cmd->hooks, cmd->num_hooks, n);
+        }
+    }
+}
+
 bool mp_hook_test_completion(struct MPContext *mpctx, char *type)
 {
     struct command_ctx *cmd = mpctx->command_ctx;

player/command.h

@@ -117,6 +117,7 @@ void mp_hook_start(struct MPContext *mpctx, char *type);
 int mp_hook_continue(struct MPContext *mpctx, int64_t client_id, uint64_t id);
 void mp_hook_add(struct MPContext *mpctx, char *client, int64_t client_id,
                  const char *name, uint64_t user_id, int pri);
+void mp_remove_client_hooks(struct MPContext *mpctx, int64_t client_id);
 
 void mark_seek(struct MPContext *mpctx);