On BlazorBootstrapLayout, main should have role="main"

[a99cl208]

From Google Lighthouse accessibility audit: https://dequeuniversity.com/rules/axe/4.11/landmark-one-main

role="main" should be added on the

element here: https://github.com/vikramlearning/blazorbootstrap/blob/main/blazorbootstrap/Components/Layout/BlazorBootstrapLayout.razor