Support for "description" overrides in YAML join definitions

[IrakliJani]

Description

join definitions in yaml permit overriding "aliases" and "labels", but they do not support overriding "descriptions"

related type:

lightdash/packages/common/src/types/explore.ts

Lines 11 to 20 in 579c111

	export type ExploreJoin = {
	table: string; // Must match a tableName in containing Explore
	sqlOn: string; // Built sql
	type?: DbtModelJoinType; // Optional join type
	alias?: string; // Optional alias for the joined tableName
	label?: string; // Optional UI label override for the underlying table
	hidden?: boolean;
	fields?: string[]; // Optional list of fields to include from the joined table
	};