Icons next to CalDAV/CardDAV tab titles (#1599)

* Icons next to CalDAV/CardDAV tab titles

Signed-off-by: Arnau Mora <arnyminerz@proton.me>

* Use shared element transitions

* Switch to `sharedBounds` to allow font size changes

* Update app/src/main/kotlin/at/bitfire/davdroid/ui/account/AccountScreen.kt

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Minor changes

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Signed-off-by: Arnau Mora <arnyminerz@proton.me>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Ricki Hirner <hirner@bitfire.at>