Panic when using an azure object store with an invalid access key

[scsmithr]

Describe the bug

When using an azure object store configured with an invalid access key, attempting to use the store will result in a panic.

To Reproduce

Example:

use object_store::azure::MicrosoftAzureBuilder;
use object_store::{path::Path, ObjectStore};

#[tokio::main]
async fn main() {
    let store = MicrosoftAzureBuilder::new()
        .with_account("my_account")
        .with_container_name("my_container")
        .with_access_key("invalid")
        .build()
        .unwrap();

    let path = &Path::parse("/my_path").unwrap();
    let _res = store.get(&path).await;
}

Results in a panic during the get:

thread 'main' panicked at /Users/sean/.cargo/registry/src/index.crates.io-6f17d22bba15001f/object_store-0.7.1/src/azure/credential.rs:189:56:
called `Result::unwrap()` on an `Err` value: InvalidPadding

Expected behavior

No panic and instead an error gets returned.

The easy fix is to just propagate the error up from here:

arrow-rs/object_store/src/azure/credential.rs

Lines 170 to 182 in 03d0505

	/// Generate signed key for authorization via access keys
	/// <https://docs.microsoft.com/en-us/rest/api/storageservices/authorize-with-shared-key>
	fn generate_authorization(
	h: &HeaderMap,
	u: &Url,
	method: &Method,
	account: &str,
	key: &str,
	) -> String {
	let str_to_sign = string_to_sign(h, u, method, account);
	let auth = hmac_sha256(BASE64_STANDARD.decode(key).unwrap(), str_to_sign);
	format!("SharedKey {}:{}", account, BASE64_STANDARD.encode(auth))
	}

Additional context

Our use case is we configure object stores based on user provided values, and so a panic when provided with an invalid value is undesirable.

[tustvold]

Agreed, we should probably check this on construction within the builder

[tustvold]

label_issue.py automatically added labels {'object-store'} from #4974