[DDW-657] Fix blank currency selection after updating to 4.0.5

[thedanheller]

This PR fixes blank currency selection after updating to 4.0.5

Todos

• Change the localStorage to store only the currency code
• update Wallets store to grab the currency from the local stored currency code

Old localStorage currency format

	"staging-CURRENCY-SELECTED": {
		"symbol": "brl",
		"decimalDigits": 2,
		"name": "Brazilian Real",
		"symbolNative": ""
	}

New localStorage currency format

	"staging-CURRENCY-SELECTED": "brl"

Steps to test

Daedalus builds

1. Run a Daedalus version older than 4.0.5 and set a currency different than USD;
2. Run Daedalus 4.0.5 version: the currency should be broken as described at the Jira card;
3. Run this PR's build: the currency feature should be working normally.

Running Daedalus locally

1. Set the CURRENCY-SELECTED value at config.json to:

	"[ENVIRONMENT]-CURRENCY-SELECTED": {
		"symbol": "brl",
		"decimalDigits": 2,
		"name": "Brazilian Real",
		"symbolNative": ""
	}

2. Run Daedalus in the develop branch: the currency should be broken as described at the Jira card;
3. Run Daedalus in the branch fix/ddw-657-fix-blank-currency-selection-after-updating-to-4-0-5: the currency feature should be working normally.

Screenshots

With error

Without error

---

Testing Checklist

• Slack QA thread
• Jira card
• Test

---

Test Scenario

Scenario 1 - Validate is the balance is displayed on other currencies

Given that Daedalus 4.0.4 is installed
And It has a wallet
And the option to show balance in other currencies is enabled in "Settings- Wallets"
When I update to 4.0.5
And I check the option to show balance in other currencies
Then I can see the dropdown maintains the selection as it was on 4.0.4
And I can see the balance on the wallet is displayed on the selected currency

---

Review Checklist

Basics

• PR has been assigned and has appropriate labels (feature/bug/chore, release-x.x.x)
• PR is updated to the most recent version of the target branch (and there are no conflicts)
• PR has a good description that summarizes all changes
• PR has default-sized Daedalus window screenshots or animated GIFs of important UI changes:
  • In English
  • In Japanese
• CHANGELOG entry has been added to the top of the appropriate section (Features, Fixes, Chores) and is linked to the correct PR on GitHub
• Automated tests: All acceptance and unit tests are passing (yarn test)
• Manual tests (minimum tests should cover newly added feature/fix): App works correctly in development build (yarn dev)
• Manual tests (minimum tests should cover newly added feature/fix): App works correctly in production build (yarn package / CI builds)
• There are no flow errors or warnings (yarn flow:test)
• There are no lint errors or warnings (yarn lint)
• There are no prettier errors or warnings (yarn prettier:check)
• There are no missing translations (running yarn manage:translations produces no changes)
• Text changes are proofread and approved (Jane Wild / Amy Reeve)
• Japanese text changes are proofread and approved (Junko Oda)
• UI changes look good in all themes (Alexander Rukin)
• Storybook works and no stories are broken (yarn storybook)
• In case of dependency changes yarn.lock file is updated

Code Quality

• Important parts of the code are properly commented and documented
• Code is properly typed with flow
• React components are split-up enough to avoid unnecessary re-renderings
• Any code that only works in main process is neatly separated from components

Testing

• New feature/change is covered by acceptance tests
• New feature/change is manually tested and approved by QA team
• All existing acceptance tests are still up-to-date
• New feature/change is covered by Daedalus Testing scenario
• All existing Daedalus Testing scenarios are still up-to-date

After Review

• Merge the PR
• Delete the source branch
• Move the ticket to done column on the YouTrack board
• Update Slack QA thread by marking it with a green checkmark

[gabriela-ponce]

Looks good 🎉