Test that implement AbstractUpgradeTestCase fail with deprecation warnings

[jkakavas]

AbstractUpgradeTestCase#setupForTest() does a "template exists" request

elasticsearch/x-pack/qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/AbstractUpgradeTestCase.java

Lines 84 to 100 in 0aa66b0

	public void setupForTests() throws Exception {
	awaitBusy(() -> {
	boolean success = true;
	for (String template : templatesToWaitFor()) {
	try {
	final boolean exists = adminClient()
	.performRequest(new Request("HEAD", "_template/" + template))
	.getStatusLine().getStatusCode() == 200;
	success &= exists;
	logger.debug("template [{}] exists [{}]", template, exists);
	} catch (IOException e) {
	logger.warn("error calling template api", e);
	}
	}
	return success;
	});
	}

which now started to throw deprecation warnings for types removal

> Warnings: [[types removal] The response format of get index template requests will change in the next major version. Please start using the `include_type_name` parameter set to `false` in the request to move to the new, typeless response format that will be the default in 7.0.]

and makes all tests fail. I assume we can just add setOptions(allowTypeRemovalWarnings()) to the request but seeing this is also a deprecated method, is there any better way?

[elasticmachine]

Pinging @elastic/es-search

[jkakavas]

I took a swing at it in #38396 , in case setOptions(allowTypeRemovalWarnings()) is the way to go