Add Debug Credentials Again

[theck13]

Fix

Add populating the values of the loginEmail and loginPassword items in the gradle.properties file in the email and password fields for debug builds. If the values are set in gradle.properties, they will be inserted into the fields for the login flow. Otherwise, the fields will be empty.

These same changes were added previously in Add Debug Credentials, but they were removed when SimplenoteCredentialsActivity.java was replaced with NewCredentialsActivity.kt.

Test

0. Clear app data.
1. Tap Sign Up button.
2. Notice Email field is empty.
3. Tap back arrow in app bar.
4. Tap Log In button.
5. Tap "We'll email you a code..." button.
6. Notice Email and Password fields are populated with loginEmail and loginPassword values from gradle.properties.

Review

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Release

These changes do not require release notes.