fix: lifecycle_rule optional condition is_live failing when missing

[antoinedeschenes]

As of the latest terraform version (1.4.6), the module fails when the optional "is_live" condition is missing, with the following error message:

Invalid value for "default" parameter: the default value must have the same type as the map elements.

│ Error: Invalid function argument
│ 
│   on main.tf line 81, in resource "google_storage_bucket" "bucket":
│   81:         with_state                 = lookup(lifecycle_rule.value.condition, "with_state", lookup(lifecycle_rule.value.condition, "is_live", false) ? "LIVE" : null)
│ 
│ Invalid value for "default" parameter: the default value must have the same
│ type as the map elements.

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[apeabody]

/gcbrun

[apeabody]

/gcbrun

[apeabody]

Thanks for the contribution @antoinedeschenes!