Website logos and informative icons from the email report are not displayed

[CiprianGeorgiu]

[Affected versions]:

• Firefox 62.0

[Affected Platforms]:

• Windows 10 x64
• macOS 10.13
• Ubuntu 16.04 x64

[Steps to reproduce]:

1. Launch Firefox.
2. Go to https://fx-breach-alerts.herokuapp.com/
3. Subscribe with a valid email address (compromised or uncompromised).
4. Click on the "Verify your subscription" link from Inbox.

[Expected result]:

• The website logos (in case of a brached email report) and the four icons (not breached) from the email report are properly displayed.

[Actual result]:

• The website logos are not displayed in the email report nor the four icons which inform the user about the steps should take for a secured account.
  -- screenshot for the website logos: https://drive.google.com/open?id=1O5bnARvFIGyabmQCeZQ6X9VfVPEvc5Di
  -- screenshot for the informative icons: https://drive.google.com/file/d/1eItvxF2RNkIYNeuI8_xlDfg2U28Fd9d3/view

[Regression]:

• Not a regression.

[pdehaan]

I think this was from #323 (comment)

Still Needed:

• decision on what to put in place of logo images since thou shalt not send svgs to gmail.

Not sure if something like convert-svg-to-png would work here. Basically when we grab new logos from HIBP servers, we'd need to convert any SVGs to PNGs (for better web+email interop), then delete the possibly now redundant SVGs, run all PNGs though imagemin optimizer, and... that may be it.

[groovecoder]

This is fixed on https://fx-breach-alerts.herokuapp.com/ with #388 and #381