Embedded SVGs cause a wall of repeated missing image placeholders

[BenjaminNolan]

Describe the bug
We're using Mend Renovate to manage dependencies, which includes a thin SVG banner at the top of each of its PRs. When the notification is sent to Teams, the banner does not show, and five 840x840 placeholders appear after the description instead. This makes the integration unusable.

To Reproduce

1. Set up a subscription for PRs in a Teams channel
2. Wait for the PR notification to be sent, either by:
   a. Configuring Renovate on a repository and adding a package.json with an old dependency version in it, or
   b. Creating a PR with an embedded SVG in the description

Expected behavior
The image should either be displayed, or omitted completely if the target platform (ie, Teams) does not support it.

Screenshots

(cropped for length)

Desktop:

• OS: Windows 11
• Client: Teams Classic and New Teams

Additional context
This is less of an issue in the Classic Teams client as it hides long posts, so the missing images are hidden behind the "Read more" link, however this functionality seems to have been removed from the New Teams client, so every PR results in a five-to-six page scroll that's almost entirely made up of the full-width missing image squares. I realise this is more an issue with Teams itself, however as far as I can tell don't intend to support SVGs for some reason, so they should probably not be sent over as embeds until they decide to reverse this decision.

[BenjaminNolan]

Ping @jlord and @willsmythe as this feels like it's relevant to your department(s)? If not, please can you indicate who should be looking at these issues.

[jlord]

Thanks writing this up @BenjaminNolan! I'm going to also tag in @sasanktv for 👀