[compiler] Instantiate templated aliases in base position of member expression

[witemple-msft]

Closes #9655
Closes #9656

This PR adds a corresponding case for when the base of a member expression is a templated alias that only has defaultable params. This works similarly to how we handle other templated decls with only defaultable params: unless the checker options are resolving template declarations, we fully check the alias and late-bind it. This gives us a good symbol that the members can resolve through.

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commit: 4707b64

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All changed packages have been documented.

• ✅ @typespec/compiler

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@typespec/compiler - fix ✏️

Fixed an issue where referencing a member of a templated alias with defaultable parameters would fail to instantiate the alias, leaking template parameters.

[azure-sdk]

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🛝 Playground	🌐 Website	🛝 VSCode Extension

[witemple-msft]

#9655 : https://cadlplayground.z22.web.core.windows.net/prs/9670/?e=%40typespec%2Fopenapi3&c=YWxpYXMgRm9vPFQ%2BICA9IHsKICB0OiBUOwp9OwoKCm1vZGVsIFRlc3TFGnByb3A6xC4udAp9&options=%7B%7D&vs=%7B%7D

#9656 : https://cadlplayground.z22.web.core.windows.net/prs/9670/?e=%40typespec%2Fopenapi3&c=aW1wb3J0ICJAdHlwZXNwZWMvaHR0cCI7Cgp1c2luZyBUeXBlU3BlYy5IdHRwOwoKbW9kZWwgUmVzIHsKICBleGFtcGxlOiBpbnQzMjsKfQoKaW50ZXJmYWNlIEZhY3Rvcnk8VD7FLEFjdGlvbjxSZXNvdXJjZSBleHRlbmRzIFJlZmxlxRwuTcRdPihAYm9keVJvb3QgcmVzOsRtxTIpOiBUxWNhbGlhcyBPcGVyYcQ3czxUID0gc3RyaW5nPiA9y3g7CgpvcCBjcmVhdGVPclJlcGzkAJhpzDwu6gCXPjsK&options=%7B%7D&vs=%7B%7D