4.3.3 Backport

[barchetta]

Backport the following PRs to helidon-4.3.x

• Do not switch to chunked encoding in webclient when the length is known #10828 (4.3.3: Do not switch to chunked encoding in webclient when the length is known #10854)
• Terminate monitor thread created by the timeout implementation when supplier returns #10833 (4.3.3: Terminate monitor thread created by the timeout implementation when supplier returns #10855)
• 4.x: Free disk space in _tests job #10851 (4.3.3: Free disk space in _tests job #10852)
• Improve Prometheus output performance #10850 ( 4.3.3: Improve Prometheus output performance #10856)