[msbuild] Disable stripping symbols by default for Debug builds (#20308)

Fixes https://github.com/xamarin/xamarin-macios/issues/20235

docs/configuration-properties.md

@@ -21,6 +21,7 @@ There are a number of properties that are contingent upon the configuration sett
 |--------------------------	|-------------------	|---------------------------------------	|
 | CodesignDisableTimestamp 	| true              	|                                       	|
 | DebuggerSupport          	| true              	|                                       	|
+| NoSymbolStrip          	| true              	|                                       	|
 | RuntimeIdentifiers       	| maccatalyst-x64   	| TargetFramework == netx.x-maccatalyst 	|
 | RuntimeIdentifiers       	| osx-x64           	| TargetFramework == netx.x-macos       	|
 | UseSystemResourceKeys    	| false             	|                                       	|

msbuild/Xamarin.Shared/Xamarin.Shared.props

@@ -238,6 +238,8 @@ Copyright (C) 2020 Microsoft. All rights reserved.
 		<!-- Xamarin.Mac never had an equivalent for MtouchNoSymbolStrip and was never stripped, except when using NativeAOT -> true -->
 		<!-- default to 'false' -->
 		<NoSymbolStrip Condition="'$(NoSymbolStrip)' == '' And '$(_PlatformName)' != 'macOS'">$(MtouchNoSymbolStrip)</NoSymbolStrip>
+		<!-- Disable stripping for Debug builds by default -->
+		<NoSymbolStrip Condition="'$(NoSymbolStrip)' == '' And '$(Configuration)' == 'Debug'">true</NoSymbolStrip>
 		<NoSymbolStrip Condition="'$(NoSymbolStrip)' == '' And ('$(_PlatformName)' == 'macOS' Or '$(_PlatformName)' == 'MacCatalyst') And '$(_UseNativeAot)' != 'true'">true</NoSymbolStrip>
 		<!-- Disable stripping for simulator builds by default -->
 		<NoSymbolStrip Condition="'$(NoSymbolStrip)' == '' And ('$(_PlatformName)' == 'iOS' Or '$(_PlatformName)' == 'tvOS' Or '$(_PlatformName)' == 'watchOS') And '$(ComputedPlatform)' != 'iPhone'">true</NoSymbolStrip>