apply defaultValue to overview_mode for both single and groups cases#7

mgiota wants to merge 2 commits intoslo-overview-embeddable-schema-registrationmgiota/kibana:slo-overview-embeddable-schema-registrationfrom

SCHEMA_default_value_for_overview_modemgiota/kibana:SCHEMA_default_value_for_overview_modeCopy head branch name to clipboard