Revert "control/controlclient: delete unreferenced mapSession UserProfiles"

This reverts commit 413fb5b933.

See long story in #14992

Updates #14992
Updates tailscale/corp#26058

Change-Id: I3de7d080443efe47cbf281ea20887a3caf202488
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea
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Gitea Version: 1.28.0+dev-477-g8b6ad49a5f