fix: Duplicate aliases generated in rendering when two crates of the same version (#3386)

Original cause:
5e90483#diff-52bdc04b030a02035a19a3c805288b7720191185a18f6b8f16f61a59baa42d3fR224
Related to: #3215

This PR updates rendering in `cargo-bazel` to handle the case when there
are multiple dependencies on a crate at the same version, but they're
aliased. For example, when a `Cargo.toml` has the following:

```
itertools = "0.11.24"
itertools_other = { version = "0.11.24", package = "itertools" }
```

Previously this would generate two aliases both with the name
`itertools-0.11.24` but now we only create a single alias of that name.

Encountering this case is odd but not uncommon, especially if you also
use a tool like
[`cargo-hakari`](https://github.com/guppy-rs/guppy/tree/main/tools/cargo-hakari)
in your workspace.

Author: ParkMyCar

cargo/private/cargo_toml_info/3rdparty/crates/BUILD.proc-macro2-1.0.89.bazel

@@ -140,6 +140,9 @@ cargo_build_script(
     ),
     edition = "2021",
     pkg_name = "proc-macro2",
+    rustc_env_files = [
+        ":cargo_toml_env_vars",
+    ],
     rustc_flags = [
         "--cap-lints=allow",
     ],

cargo/private/cargo_toml_info/3rdparty/crates/BUILD.serde-1.0.214.bazel

@@ -148,6 +148,9 @@ cargo_build_script(
     ),
     edition = "2018",
     pkg_name = "serde",
+    rustc_env_files = [
+        ":cargo_toml_env_vars",
+    ],
     rustc_flags = [
         "--cap-lints=allow",
     ],