[wasm] Change ICU WasmBuildTests to use wasmconsole and wasmbrowser templates

[ilonatommy]

• Change wbt icu methodology: we used to run them sending to helix, now our repo is in charge of running them with playwright (same as in WasmTemplateTests).
• Some logic from WasmTemplateTests was useful to be reused with other tests, so it got moved to WasmTemplateTestsBase that will be a base class for all the other WBT that will be transformed to template-based.
• Rename PredefinedIcudt to CustomIcuFile - it describes better what we're doing. This is not a public name.
• Functionality of tests did not change.

issues discovered - to be addressed in a follow-up PR, this one is already big enough. They are all connected with transition from WasmAppBuilder to Wasm SDK:

• wasmconsole does not require custom filename to start with "icudt" when wasmbrowser does. The error messages are different, see NonExistingCustomFileAssertError. wasmconsole should start using wasm sdk and drop WasmAppBuilder: [browser] Migrate wasmconsole template to WebAssembly SDK #102743.
• wasmbrowser stopped working with WasmIcuDataFileName but works with BlazorIcuDataFileName. While the functionality is preserved, the naming does not make sense - it's not a blazor app. Similar with WasmIncludeFullIcuData vs BlazorWebAssemblyLoadAllGlobalizationData. It will be fixed by [browser] Replace "blazor" prefix with "wasm" for common MSBuild properties #94133.
• CustomIcuShard fails for isOnlyPredefinedCultures = true with wasmbrowser - blazor does not throw on isOnlyPredefinedCultures = true, issue: [browser] OnlyPredefinedCultures=true does not throw an exception when culture is missing #108272

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