issue #1378 WKD client timeout test

[IvanPizhenko]

This PR adds timeout test for the WKD client and introduces few small fixes to the WKD client itself

close #1378

related issue #1317

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Tests (delete all except exactly one):

• Tests added or updated

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To be filled by reviewers

I have reviewed that this PR... (tick whichever items you personally focused on during this review):

• addresses the issue it closes (if any)
• code is readable and understandable
• is accompanied with tests, or tests are not needed
• is free of vulnerabilities

[DenBond7]

unfortunately, it looks too complicated. Please look at com.flowcrypt.email.rules.FlowCryptMockWebServerRule and an examle of usage

flowcrypt-android/FlowCrypt/src/androidTest/java/com/flowcrypt/email/ui/activity/enterprise/SignInActivityEnterpriseTest.kt

Line 75 in 8e38333

val mockWebServerRule =

flowcrypt-android/FlowCrypt/src/androidTest/java/com/flowcrypt/email/ui/activity/enterprise/SignInActivityEnterpriseTest.kt

Line 320 in 8e38333

val delayInMilliseconds = 6000

[IvanPizhenko]

FlowCryptMockWebServerRule is not available here since this is not "Android Test". However I've looked at it and it gives me idea to use okhttp MockWebServer.

[DenBond7]

I meant that it would be better to use a mock web server instead of sockets. It will be clearer.

[IvanPizhenko]

@DenBond7 Reworked it, please have a look again.