- We need to indicate when login comes from UI to make sure (in future) user accepted terms of use & privacy, not being logged in automatically.
- it helps make `source` field required ([[ https://linear.app/comm/issue/ENG-1870/make-source-a-required-parameter-to-login-function-in-lib | task ]]), previously when the user was logging form UI `source` was undefined
As an alternative, we can use only sth like: `LOG_IN_FROM_FORM` and `PlatformDetails` to distinguish between web/native, but I think it's safer to rely only on one specific param.