Bug: Self-hosted sites Reader Tab does not default to Discover

Expected behavior

When logging in with a self-hosted and tapping the “Reader” tab, the default tab should be “Discover”.

Actual behavior

When logging in with a self-hosted and tapping the “Reader” tab, the default tab is "Following"

Notes from Slack Chat

• The "following" readerTag is manually created as the defaultInMemory value for self-hosted sites in LoadReaderTabsUseCase (see here)
• Expecting appPrefsWrapper.getReaderTag()? to return null and tagList.find { it.isDefaultSelectedTab() } to set the Discover tab (see here)
• The onTagChanged event is raised from

_uiState.value = ContentUiState(
        tagList.map { it.label },
        tagList,
        searchIconVisible = isSearchSupported(),
        settingsIconVisible = isSettingsSupported()
)

However this event is raised multiple times and not before the default is set from ReaderViewModel.start.loadtabscall

I pushed my log line branch issue/14565-reader-tab-not-default-to-discover-logs.

Start with LoadReaderTabsUseCase.kt, especially the self-hosted defaultInMemory readerTag, then trace ReaderViewModel.start.loadtabs and the onTagChanged event described in ReaderViewModel.kt. Done means opening Reader on a self-hosted site selects Discover by default rather than Following, without changing the expected behavior for other sites.