updates for coastline extraction imagery sample

[cariashuang0417]

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This pr contains changes for map widget related codes for sample coastline-extraction-usa-landsat8-multispectral-imagery:

• protected the final result of extracted coastline web map in geosaurus online
• update code for creating map, add layers, center, and zoom level
• map screenshots didn't change as the sample data input didn't change
• note: I was able to run and get the same result for the first and second map (usa coast polygon, landsat) and the following raster analysis layers, but I haven't get the second map (extracted coastline) as save function failed with error the allowed maximum number of rows and columns is 4000 and 4000 respectively. Will investigate the error and make any change if needed.
• maps shows correctly on locally built developer website

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