fix: use symbol-provider for accessors in member-builder

[haydenbaker]

Motivation and Context

• setter method (set_meta) conflicts with built in set_meta for error metadata in generated client #4338
• needs testing
• ideally, wouldn't need to do this, but would require changing the strategy for adding non-members to the builder (ex: meta field for error_metadata)
• naively strips a r## prefix from accessors, but we should probably be more clever here

Checklist

• For changes to the smithy-rs codegen or runtime crates, I have created a changelog entry Markdown file in the .changelog directory, specifying "client," "server," or both in the applies_to key.
• For changes to the AWS SDK, generated SDK code, or SDK runtime crates, I have created a changelog entry Markdown file in the .changelog directory, specifying "aws-sdk-rust" in the applies_to key.

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[rcoh]

😅

[landonxjames]

Closing in favor of #4342