[wasm] Change TrimMode setting for templates, and tests (#80639)

* [wasm] Set TrimMode=full for templates

* [wasm] Remove TrimMode=partial default setting

.. and set TrimMode=partial for library tests.

* [wasm] don't set TrimMode explicitly for template projects. it will default to full now

eng/testing/tests.wasm.targets

@@ -6,6 +6,7 @@
     <ArchiveTests Condition="'$(WasmBuildingForNestedPublish)' == 'true'">false</ArchiveTests>
     <BundleTestAppTargets>$(BundleTestAppTargets);BundleTestWasmApp</BundleTestAppTargets>
     <DebuggerSupport Condition="'$(DebuggerSupport)' == '' and '$(Configuration)' == 'Debug'">true</DebuggerSupport>
+    <TrimMode Condition="'$(TrimMode)' == ''">partial</TrimMode>
 
     <!-- set this when provisioning emsdk on CI -->
     <EMSDK_PATH Condition="'$(EMSDK_PATH)' == '' and '$(ContinuousIntegrationBuild)' == 'true' and '$(MonoProjectRoot)' != ''">$([MSBuild]::NormalizeDirectory($(MonoProjectRoot), 'wasm', 'emsdk'))</EMSDK_PATH>

src/mono/wasm/build/WasmApp.props

@@ -4,7 +4,6 @@
     <TargetOS>browser</TargetOS>
     <RuntimeIdentifier>browser-wasm</RuntimeIdentifier>
     <UseMonoRuntime>true</UseMonoRuntime>
-    <TrimMode Condition="'$(TrimMode)' == ''">partial</TrimMode>
 
     <_WasmBuildCoreDependsOn>
         _InitializeCommonProperties;