Trigger LocationChanging callbacks on enhanced navigation

[SteveSandersonMS]

Location changing handlers may not always be invoked on enhanced navigation. For example, when no interactive router is present, interactive components cannot intercept user-initiated navigations.

From @MackinnonBuck:

"When an enhanced navigation occurs, LocationChanged event handlers registered in interactive runtimes (i.e., Blazor Server/WebAssembly) get invoked. However, location changing handlers may or may not intercept enhanced navigations, so it's important that app logic not rely on location changing handlers being invoked reliably. For example, the user might switch to another page before an interactive runtime becomes available. In .NET 8, if server-side routing and enhanced navigation are enabled, location changing handlers will only get invoked for programmatic navigations initiated from an interactive runtime. In future .NET versions, more types of navigations (e.g., link clicks) may also invoke location changing handlers".

A more detailed analysis of when location changing handlers get invoked can be found here.