Make default window size valid for all metric types

[deshsidd]

Description

The default window size for latency, cpu and memory is 60s hardcoded on the backend:

public static final TimeValue DEFAULT_WINDOW_SIZE = new TimeValue(60, TimeUnit.SECONDS);

The valid window sizes are defined as:

public static final Set<TimeValue> VALID_WINDOW_SIZES_IN_MINUTES = new HashSet<>(
        Arrays.asList(
            new TimeValue(1, TimeUnit.MINUTES),
            new TimeValue(5, TimeUnit.MINUTES),
            new TimeValue(10, TimeUnit.MINUTES),
            new TimeValue(30, TimeUnit.MINUTES)
        )
    );

The default window size is not a valid window size based on the above.

This will break the QI dashboard since the dashboard only parses timeunit m and h:
https://github.com/opensearch-project/query-insights-dashboards/blob/main/public/pages/TopNQueries/TopNQueries.tsx#L192

Issues Resolved

Closes: #155

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