ref(nav) move isLinkActive and ProjectIcon inside components

[JonasBa]

Moves ProjectIcon inside Secondary Nav components, moves prop definitions next to component implementations and moves isLinkActive inside the primary nav component.

[JonasBa]

@malwilley I've changed this to LocationDescriptor, but lmk if it was intentional and should be preserved

[malwilley]

not intentional!

[sentry]

Bug: The isSidebarLinkActive function normalizes the to path but not the pathname argument. This causes the active state check to fail for secondary navigation links.
_{Severity: MEDIUM}

Suggested Fix

Normalize the pathname argument inside the isSidebarLinkActive function, similar to how the to argument is normalized. This will ensure both paths are compared in the same format, fixing the active state logic for secondary navigation.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent.
Verify if this is a real issue. If it is, propose a fix; if not, explain why it's not
valid.

Location: static/app/views/navigation/primary/components.tsx#L518-L522

Potential issue: The refactored `isSidebarLinkActive` function is used for both primary
and secondary navigation. For secondary navigation, it's called with a `pathname` that
includes the full URL path (e.g., `/organizations/org-slug/...`). However, the function
only normalizes its `to` argument, stripping prefixes like the organization slug. It
then compares the un-normalized `pathname` with the normalized `to` path using
`pathname.startsWith(toPathname)`. This comparison will always fail when an organization
slug is present, preventing secondary navigation links from being highlighted as active.

_{Did we get this right? 👍 / 👎 to inform future reviews.}