Add e2e tests for getBlobSidecars in beacon-chain

[nazarhussain]

There is a test file which have only one test which is skipped. It would be better to have an issue for tracking it rather the code comment.

lodestar/packages/beacon-node/test/e2e/api/impl/getBlobSidecars.test.ts

Lines 16 to 34 in 8794025

	// TODO: Write actual tests against the real BeaconChain class, this test is useless
	it.skip("getBlobSideCar From BlobSidecars", async () => {
	const block = config.getForkTypes(GENESIS_SLOT).SignedBeaconBlock.defaultValue();
	const blobSidecars = ssz.deneb.BlobSidecars.defaultValue();
	const wrappedBlobSidecars = {
	blockRoot: ssz.Root.defaultValue(),
	slot: block.message.slot,
	blobSidecars,
	};
	server.forkChoiceStub.getFinalizedBlock.returns(zeroProtoBlock);
	server.dbStub.blockArchive.get.resolves(block);
	server.dbStub.blobSidecars.get.resolves(wrappedBlobSidecars);
	const returnedBlobSideCars = await server.blockApi.getBlobSidecars("genesis");
	expect(returnedBlobSideCars.data).to.equal(blobSidecars);
	});