Today content type detection on an input stream works by peeking up to
twenty bytes into the stream. If the stream is headed by more whitespace
than twenty bytes, we might fail to detect the content type. We should
be ignoring this whitespace before attempting to detect the content
type. This commit does that by ignoring all leading whitespace in an
input stream before attempting to guess the content type.

…pe-detection-with-leading-whitespace

* elastic/master: (34 commits)
  Cross-cluster search: preserve cluster alias in shard failures (elastic#32608)
  Handle AlreadyClosedException when bumping primary term
  [TEST] Allow to run in FIPS JVM (elastic#32607)
  [Test] Add ckb to the list of unsupported languages (elastic#32611)
  SCRIPTING: Move Aggregation Scripts to their own context (elastic#32068)
  Painless: Use LocalMethod Map For Lookup at Runtime (elastic#32599)
  [TEST] Enhance failure message when bulk updates have failures
  [ML] Add ML result classes to protocol library (elastic#32587)
  Suppress LicensingDocumentationIT.testPutLicense in release builds (elastic#32613)
  [Rollup] Update wire version check after backport
  Suppress Wildfly test in FIPS JVMs (elastic#32543)
  [Rollup] Improve ID scheme for rollup documents (elastic#32558)
  ingest: doc: move Dot Expander Processor doc to correct position (elastic#31743)
  [ML] Add some ML config classes to protocol library (elastic#32502)
  [TEST]Split transport verification mode none tests (elastic#32488)
  Core: Move helper date formatters over to java time (elastic#32504)
  [Rollup] Remove builders from DateHistogramGroupConfig (elastic#32555)
  [TEST} unmutes SearchAsyncActionTests and adds debugging info
  [ML] Add Detector config classes to protocol library (elastic#32495)
  [Rollup] Remove builders from MetricConfig (elastic#32536)
  ...