[BUG] Custom layer get error when change zoom level

[junqiu-lei]

What is the bug?

When adjust zoom values in custom layer, it will catch error and unable to show the layer.

Browser console error:

customImportMapDashboards.plugin.js:6 Error: layers.ee87a035-df8a-4da5-9455-16dd538a317e.minzoom: number expected, string found
    at Object.kn [as emitValidationErrors] (customImportMapDashb….plugin.js:6:246184)
    at Yt (customImportMapDashb….plugin.js:6:583615)
    at ee._validate (customImportMapDashb….plugin.js:6:606407)
    at ee.addLayer (customImportMapDashb….plugin.js:6:597550)
    at Map.addLayer (customImportMapDashb….plugin.js:6:834950)
    at addNewLayer (customImportMapDashb…plugin.js:16:375139)
    at Object.render (customImportMapDashb…plugin.js:16:376479)
    at handleBaseLayerRender (customImportMapDashb…plugin.js:13:311018)
    at customImportMapDashb…plugin.js:13:294673
    at os (osd-ui-shared-deps.js:435:83209)

Tested in OSM layer and document layers, no issue happened there.

How can one reproduce the bug?

1. Create custom layer
2. Edit zoom levels under settlings
3. Update

What is the expected behavior?

The zoom level should be able to adjust properly in custom layer.

What is your host/environment?

3.0.0 main branch