Remove dev dependency on openssl

[tustvold]

Which issue does this PR close?

Relates to #576

Rationale for this change

Noticed whilst poking around on #576

Before

cargo tree -i openssl --all-features
openssl v0.10.73
└── native-tls v0.2.14
    ├── hyper-tls v0.6.0
    │   └── reqwest v0.12.15
    │       └── object_store v0.12.4 (/home/raphael/repos/external/arrow-rs-object-store)
    │       [dev-dependencies]
    │       └── object_store v0.12.4 (/home/raphael/repos/external/arrow-rs-object-store)
    ├── reqwest v0.12.15 (*)
    └── tokio-native-tls v0.3.1
        ├── hyper-tls v0.6.0 (*)
        └── reqwest v0.12.15 (*)

After

$ cargo tree -i openssl --all-features
error: package ID specification `openssl` did not match any package

What changes are included in this PR?

Are there any user-facing changes?

[tustvold]

Without this it will bring in the default TLS setup