Support alter refresh interval on external scheduler

[noCharger]

Description

Support alter refresh interval on external scheduler

Test Scenario	Expectation	Result
External scheduler Alter refresh interval to value >= interval threshold	Interval updated	refresh interval updated successfully
External scheduler Alter refresh interval to value < interval threshold	throws exception	java.lang.IllegalArgumentException: Input refresh_interval is 4 Minutes, required above the interval threshold of external scheduler: 5 minutes
External scheduler Alter refresh interval to random string which can't be parsed by spark	throws exception	"error": """{"Message":"Fail to run query. Cause: Error parsing '4 abc' to interval, invalid unit 'abc'"}"""
External scheduler Alter to internal scheduler with refresh interval change	throws exception	Altering index when auto_refresh remains true and scheduler_mode is internal only allows changing: Set(scheduler_mode). Invalid options: Set(refresh_interval)
Internal scheduler Alter refresh interval	throws exception	Altering index when auto_refresh remains true and scheduler_mode is internal only allows changing: Set(scheduler_mode). Invalid options: Set(refresh_interval)

Issues Resolved

#704

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