CLI update advisory needs to be aware of the executing tool's location

[Xeevis]

Commit by @ebicoglu d372b9c introduced regression in a way user is advised to update to a new version. New code assumes tool is always in a default (global) location which is:

OS	Path
Linux/macOS	$HOME/.dotnet/tools
Windows	%USERPROFILE%\.dotnet\tools

This however won't be the case if tool is installed with --tool-path switch. To demonstrate how would that be problematic:

PS> dotnet tool install --tool-path "C:\AbpTool" Volo.Abp.Cli
PS> C:\AbpTool\abp
[21:56:55 WRN] ABP CLI has a newer stable version ...
[21:56:55 WRN] Update Command:
[21:56:55 WRN] dotnet tool update -g Volo.Abp.Cli
PS> dotnet tool update -g Volo.Abp.Cli
Tool 'volo.abp.cli' is not currently installed.

This is the reason why -g wasn't used in the advisory, with --tool-path it works universally, no matter where is the tool installed. It's possible to use -g, but it's necessary to first determine if executing tool is indeed in it's default location.