…ild properties. (#23629)

If you run `dotnet-dsrouter ios`, it says:

    Start an application on ios device with ONE of the following environment variables set:
    [Default Tracing]
    DOTNET_DiagnosticPorts=127.0.0.1:9000,nosuspend,listen
    [Startup Tracing]
    DOTNET_DiagnosticPorts=127.0.0.1:9000,suspend,listen

Setting `$DOTNET_DiagnosticPorts` is non-trivial, so as a step to simplify this, we are adding multiple MSBuild properties to configure this value.

This would allow the log message to say:

    Build and run an iOS application such as:
    [Default Tracing]
    dotnet run -c Release -p:ios-arm64 -p:DiagnosticAddress=127.0.0.1 -p:DiagnosticPort=9000 -p:DiagnosticSuspend=false -p:DiagnosticListenMode=listen
    [Startup Tracing]
    dotnet run -c Release -p:ios-arm64 -p:DiagnosticAddress=127.0.0.1 -p:DiagnosticPort=9000 -p:DiagnosticSuspend=true -p:DiagnosticListenMode=listen

Since these are all default values, it can be simplified to:

    Build and run an iOS application such as:
    [Default Tracing]
    dotnet run -p:ios-arm64 -c Release -p:EnableDiagnostics=true
    [Startup Tracing]
    dotnet run -p:ios-arm64 -c Release -p:EnableDiagnostics=true

Setting any of the new properties also implicitly means that `$(EnableDiagnostics)` is set to `true` (first example), or alternatively `$(EnableDiagnostics)` can be set to true to get the default value for all the new properties (second example).

Ref: dotnet/android#10351

Backport of #23429.

---------

Co-authored-by: Jonathan Peppers <jonathan.peppers@microsoft.com>

Context: dotnet/android#10351
Context: dotnet/macios#23429

We are adding new MSBuild properties to simplify setting
`$DOTNET_DiagnosticPorts` on mobile:

* `$(DiagnosticAddress)`
* `$(DiagnosticPort)`
* `$(DiagnosticSuspend)`
* `$(DiagnosticListenMode)`
* `$(DiagnosticConfiguration)` if you want to specify the full value
yourself, escape `,` with `%2c`, etc.

We will ship these properties in future releases of .NET 9 and 10.

To improve `dsrouter` the current log message:

Start an application on android device with ONE of the following
environment variables set:
    [Default Tracing]
    DOTNET_DiagnosticPorts=127.0.0.1:9000,nosuspend,connect
    [Startup Tracing]
    DOTNET_DiagnosticPorts=127.0.0.1:9000,suspend,connect

Will change to:

    Build and run an Android application such as:
    [Default Tracing]
dotnet build -t:Run -c Release -p:DiagnosticAddress=127.0.0.1
-p:DiagnosticPort=9000 -p:DiagnosticSuspend=false
-p:DiagnosticListenMode=connect
    [Startup Tracing]
dotnet build -t:Run -c Release -p:DiagnosticAddress=127.0.0.1
-p:DiagnosticPort=9000 -p:DiagnosticSuspend=true
-p:DiagnosticListenMode=connect

Note that `dotnet run` *does work*, but it doesn't show good progress on
the build & deploy steps as compared to `dotnet build -t:Run` and
MSBuild's terminal logger. It can take several seconds to run a
`Release` build. I think it's better to recommend `-t:Run` until we
improve `dotnet run`.