[OUI Docs] Audit docs site for use of Cascadia

[KrooshalUX]

Noticed on this page https://oui.opensearch.org/1.2/#/layout/page-header there is a mention of Cascadia. Unsure if perhaps there was a find>replace of Amsterdam at some point in favor of Cascadia, or what its origins are. Since we are no longer using the term Cascadia, we need to find a replacement for it in any potential mention on the docs site.

note: this is a separate issue from the issues already reported about the Kibana icon and mentions of elastic that are changes that have not been successfully backported

[BSFishy]

This is fixed in main and 1.x as part of #835. The next release will have this updated:

oui/src/components/page/_restrict_width.ts

Lines 45 to 51 in 54d5011

	/**
	* Sets the max-width of the page,
	* set to `true` to use the default size of `1000px`,
	* set to `false` to not restrict the width,
	* set to a number for a custom width in px,
	* set to a string for a custom width in custom measurement.
	*/