[Storage] Remove DeclarativeHotplugVolumes feature gate enablement - #5987

pytest-check-s390x: OK ✔ in 2 minutes 35.74 seconds
pytest-check-arm64: OK ✔ in 3 minutes 5.19 seconds
utilities-unittests: OK ✔ in 4 minutes 3.55 seconds
pytest-check-multiarch: OK ✔ in 4 minutes 59.95 seconds
unused-code: OK ✔ in 10 minutes 14.89 seconds
  pytest-check-x86: OK (1042.64=setup[47.01]+cmd[125.65,61.11,34.72,31.97,17.29,21.39,37.31,15.15,376.94,274.12] seconds)
  pytest-check-arm64: OK (185.19=setup[41.43]+cmd[143.76] seconds)
  pytest-check-s390x: OK (155.74=setup[39.74]+cmd[116.00] seconds)
  pytest-check-multiarch: OK (299.95=setup[35.13]+cmd[154.33,78.64,31.86] seconds)
  unused-code: OK (614.89=setup[535.31]+cmd[79.58] seconds)
  utilities-unittests: OK (243.55=setup[42.56]+cmd[200.25,0.75] seconds)
  congratulations :) (1042.82 seconds)