fix(ObjectStore/S3): switch to more reliable doesObjectExistV2

The non-v2 version is deprecated, but more importantly the V2 implementation makes fewer assumptions about ambiguous or unexpected status codes. For example, a 403 would result in a false (object does not exist) in V1, but that's not necessarily what that means. V2 returns true/false on a much more narrow set of scenarios. And it throws for all others so they can be diagnosed properly.

Signed-off-by: Josh <josh.t.richards@gmail.com>

lib/private/Files/ObjectStore/S3ObjectTrait.php

@@ -266,8 +266,11 @@ trait S3ObjectTrait {
 		]);
 	}
 
+	/**
+	 * @throws S3Exception|\Exception if there is an unhandled exception
+	 */
 	public function objectExists($urn) {
-		return $this->getConnection()->doesObjectExist($this->bucket, $urn, $this->getSSECParameters());
+		return $this->getConnection()->doesObjectExistV2($this->bucket, $urn, false, $this->getSSECParameters());
 	}
 
 	public function copyObject($from, $to, array $options = []) {