Remove sparse registry config (#2990)

Closes #2766.

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.cargo/config.toml

@@ -1,7 +1,3 @@
 [build]
 # Share one `target` directory at the project root for all Cargo projects and workspaces in smithy-rs
 target-dir = "target"
-
-# TODO(https://github.com/awslabs/smithy-rs/issues/2766): The sparse registry config can be removed when upgrading to Rust 1.70
-[registries.crates-io]
-protocol = "sparse"

aws/sdk/integration-tests/webassembly/.cargo/config.toml

@@ -3,7 +3,3 @@ target = "wasm32-wasi"
 
 [target.wasm32-wasi]
 rustflags = ["-C", "opt-level=1"]
-
-# TODO(Rust 1.70): The sparse registry config can be removed when upgrading to Rust 1.70
-[registries.crates-io]
-protocol = "sparse"

tools/.cargo/config.toml

@@ -2,7 +2,3 @@
 # Tools shouldn't share `target` with the rest of the project to
 # avoid thrash from differing compiler flags
 target-dir = "target"
-
-# TODO(Rust 1.70): The sparse registry config can be removed when upgrading to Rust 1.70
-[registries.crates-io]
-protocol = "sparse"