docs: update WMTS examples to use https for basemap.nationalmap.gov

[parthpetkar]

Description
I have fixed the issue of #12375 by updating the file packages/engine/Source/Scene/WebMapTileServiceImageryProvider.js. The changes were made at:

Line 60: Changed http to https
Line 74: Changed http to https
After building the code, it is working as expected. Attached is a screenshot demonstrating the successful fix.

Issue Number and Link
Fixes #12375.

Testing Plan
Reproduced the issue by running the original code.
Made the updates to replace http with https.
Built and tested the updated code to verify that the issue is resolved.

Author checklist

• I have submitted a Contributor License Agreement
• I have added my name to CONTRIBUTORS.md
• I have updated CHANGES.md with a short summary of my change
• I have added or updated unit tests to ensure consistent code coverage
• I have updated the inline documentation, and included code examples where relevant
• I have performed a self-review of my code

[github-actions]

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[parthpetkar]

I have signed the CLA

[ggetz]

Hi @parthpetkar, thanks for the PR!

@lukemckinstry could you please review?

[lukemckinstry]

The tile service links in the documentation now work again using http without throwing errors. It seems something changed with the data provider. Do you see this too now @parthpetkar? Perhaps switching to https is no longer necessary.

[parthpetkar]

@lukemckinstry I tried with http for me it still does not work. Here is an image to showcase that

This is the code i tried in the sandcastle:

  const viewer = new Cesium.Viewer("cesiumContainer", {
  shouldAnimate: true,
});
// Example 2. USGS shaded relief tiles (RESTful)
const shadedRelief2 = new Cesium.WebMapTileServiceImageryProvider({
    url : 'http://basemap.nationalmap.gov/arcgis/rest/services/USGSShadedReliefOnly/MapServer/WMTS/tile/1.0.0/USGSShadedReliefOnly/{Style}/{TileMatrixSet}/{TileMatrix}/{TileRow}/{TileCol}.jpg',
    layer : 'USGSShadedReliefOnly',
    style : 'default',
    format : 'image/jpeg',
    tileMatrixSetID : 'default028mm',
    maximumLevel: 19,
    credit : new Cesium.Credit('U. S. Geological Survey')
});
viewer.imageryLayers.addImageryProvider(shadedRelief2);

But this works with https