Embedded calendar always has vertical scroll bar

Steps to reproduce

1. Get a calendar embed link from Nextcloud. You get this by sharing a calendar, then under Share Link selecting "copy embed code"
2. The code looks like: https://nephele.thumbs.place/index.php/apps/calendar/embed/kXwQ72R54o9d3aYP
3. Paste the embed link into the address bar of a browser.
4. You will see that the month view displays by default, and that there is a vertical scroll bar. It only scrolls a little way, to reveal what the header bar obscures.
5. If you include an iframe, it turns out that the embed code beautifully scales the calendar to fit the frame, but always with this same scroll bar. In short I would argue there's a sizing bug. That the embeded calendar should display flat with not scroll bar,

Expected behaviour

I expect to be able to embed the calendar seamlessly so it appears to be part of the page its embedded in. And for that to happen I need the iFrame always to cover the whole content and the content not to have scroll bars.

Actual behaviour

I cannot lose the vertical scroll bar of an embedded calendar.

Client configuration

Browser: Firefox 79
Operating system: Irrelevant. But Linux Mint 20.

Server configuration

Calendar app: 2.0.4
Operating system: Unbuntu 20.04
Web server: Lighttpd 1.4.55
Database: PostgreSQL 12
PHP version: 7.4.3
Nextcloud Version: 19.0.2

Start by reproducing the embedded calendar at the issue's example URL in Firefox and inspect the month view's layout and scroll container. The work is done when an embedded calendar fills its iframe content area without the unnecessary vertical scrollbar while retaining the expected header and month view.