Unable to import a BTS 0.9.3c key export file (.json) to wallet.bitshares.org (or Bitshares UI)

**Describe the bug**
It is not possible to import a BTS 0.9.3c key file (.json) to wallet.bitshares.org (or Bitshares UI), after exporting after exporting it using the `wallet_export_keys` command.

The `wallet_export_keys` command is used as the native export command in the application menu is bugged, as per several articles,

**To Reproduce**
Steps to reproduce the behavior:
1. Go to https://wallet.bitshares.org/ or use the latest version of `Bitshares UI`
2. Login using a `key file (local wallet`
3. Go to `menu`, at the top right
4. Click `settings`
5. Click `Restore/Import`
6. Select `Import a BTS 0.9.3c key file (.json)`, from the top menu
7. Click `Choose File`
8. Browse and select your `BTS 0.9.3c key file (.json)`
9. Enter your password and click `SUBMIT`

The error can be visible while having the browser console open (i.e. in Microsoft Edge via pressing F12). The resulting error message is

> vendor.69f460f031d874f0f6fc.js:40 Uncaught TypeError: Cannot read property 'length' of undefined
> at c.o.update (vendor.69f460f031d874f0f6fc.js:40)
> at c._update (vendor.69f460f031d874f0f6fc.js:40)
> at c.a.update (vendor.69f460f031d874f0f6fc.js:41)
> at Module.u (vendor.69f460f031d874f0f6fc.js:6)
> at t.value (existing-account.45434f696d147117c1c9.js:1)
> at Object.s (vendor.69f460f031d874f0f6fc.js:144)
> at h (vendor.69f460f031d874f0f6fc.js:144)
> at vendor.69f460f031d874f0f6fc.js:144
> at y (vendor.69f460f031d874f0f6fc.js:144)
> at at (vendor.69f460f031d874f0f6fc.js:144)

**Expected behavior**
It is expected that the keys from the .json file are well imported and balances can be claimed from the `Balance Claims` option in the `Local Wallet` menu in `Settings`

**Screenshots**
Screenshot attached.


**Desktop (please complete the following information):**
- OS: Windows 10
- Browser: **Microsoft Edge** (v90.0.818.56) / **Brave** (v1.24.85 Chromium: 90.0.4430.212 / **Chrome** (v90.0.4430.212)

**Smartphone (please complete the following information):**
- Device: iPhoneSE
- OS: 14.4.2
- Browser: **Safari** (v14)

Start by reproducing the import flow in wallet.bitshares.org or Bitshares UI with a BTS 0.9.3c key file and inspect the browser console error in existing-account.45434f696d147117c1c9.js and vendor.69f460f031d874f0f6fc.js. Done means the file imports successfully and its keys are available for claiming balances through Balance Claims.

Written by the indexing model from the issue text.