Use FileExtensionHelpers more widely

[QuaintMako]

Description

We are often in need of identifying an item's type, whether it be folder, file, images or anything really.

Currently, we have rogue tests to do this work for us repeated separately in the code. For example when it comes to identify shortcuts :

OpenPath(...) in NavigationHelpers:
path.EndsWith(".lnk", StringComparison.Ordinal) || path.EndsWith(".url", StringComparison.Ordinal);

ToStorageItem(...) in StorageHelpers
if (path.EndsWith(".lnk", StringComparison.OrdinalIgnoreCase) || path.EndsWith(".url", StringComparison.OrdinalIgnoreCase))

FileExtensionHelpers.cs defines a bunch of methods that are cattled to such ends. We should enrich it and make its use wider.

Concerned code

All the codebase.

Gains

• Reduction of duplication.
• Regrouping of same logic inside a given class

Requirements

• FileExtensionHelpers.cs used more when identifying item's type.

Comments

No response

[QuaintMako]

Such helper actually exists : FileExtensionHelpers.
We need to extend its usage.

[yaira2]

Pretty sure @gave92 took care of the shortcuts.

[gave92]

#10772 took care of ".url" and ".lnk" shortcuts checks.