Remove or rework full-screen effects

In my personal experience using Element (non-enterprise and fairly high-volume and power-user like), I haven't ever encountered a situation where a full-screen effect for confetti, snow, or fireworks would've really punctuated some event in chat, reactions and emojis in the chat were enough for this, for my feeling.

Because of that, others using the feature, and/or spamming it, soon became as obnoxious and would slow my old PC down, and so I disabled the feature entirely.

I think that this feature, while interesting, should have some rework to make it more bearable (with rate-limiting it for spam, and maybe making it optionally disabled/enabled per room), or should be removed entirely (with my personal opinion that full-screen effects don't really "fit" the modern Element app)

##### Additional context

Telegram recently announced Telegram Premium, which contains an option for "premium stickers" to have full-screen effects, which reminded me of my perceived obnoxiousness of this feature in Element, and how it's prone for annoyance or abuse, or simply over-exposing the other user to an effect to the point of visual noise.

Telegram's feature is visible [here](https://telegram.org/blog/700-million-and-premium#unique-stickers), I'm not encouraging to duplicate this to Matrix, as I think it could have more averse effects in an environment such as Matrix, which has no way to regulate these kinds of stickers, and so users might find ways to create extremely annoying or harmful effects (i.e. triggering epilepsy) with them.