Eth2 Launch Pad doesn't check if some validator deposits have already been made

[emansipater]

Describe the bug

If someone resumes a previously started validator deposit by uploading their deposit data json again, and they have already made deposits for some of those validators, this is not reflected in the transaction list, which simply assumes that no deposits at all have been made yet.

To Reproduce
Steps to reproduce the behavior:

1. Go through the normal Launch Pad sequence to generate validator keystores for at least 2 validator slots
2. When you reach the deposit portion, deposit the first slot only, and then close the window
3. Open the Launch Pad page again and click through to the page where the deposit data json is uploaded.
4. Upload your previously generated deposit data json from the first time
5. Continue to the deposit page.

Expected behavior

The page should display the first deposit (or in general all previously submitted deposits) as completed or in progress, just as it did during the first time the page was loaded, so that a user resuming after any type of error (lost connection, too few funds in wallet, crashed computer, etc.) does not send extra deposits to the validator slots they have already deposited for.

Desktop (please complete the following information):

• OS: Ubuntu 18.04.5 LTS
• Brave
• Version 1.13.82 Chromium: 85.0.4183.83 (Official Build) (64-bit)

Additional context

This is an important scenario to account for as there are many ways a user can be interrupted while making their initial deposits. Optionally a more direct path to "resume making deposits" could be provided so that the user does not have to click through the entire process again, but simply ensuring that the ability to resume at all exists is obviously much more important.

[emansipater]

Whoops, didn't realise the launchpad was on a different repo. My bad!