[Storage] Remove DeclarativeHotplugVolumes feature gate enablement - #5987

pytest-check-arm64: OK ✔ in 52.37 seconds
pytest-check-s390x: OK ✔ in 52.99 seconds
utilities-unittests: OK ✔ in 1 minute 10.51 seconds
pytest-check-multiarch: OK ✔ in 1 minute 19.63 seconds
unused-code: OK ✔ in 2 minutes 44.52 seconds
  pytest-check-x86: OK (333.56=setup[12.30]+cmd[44.75,12.17,11.97,8.62,9.89,6.68,8.07,8.71,176.48,33.92] seconds)
  pytest-check-arm64: OK (52.37=setup[11.94]+cmd[40.43] seconds)
  pytest-check-s390x: OK (52.99=setup[13.57]+cmd[39.42] seconds)
  pytest-check-multiarch: OK (79.63=setup[13.39]+cmd[44.03,11.76,10.44] seconds)
  unused-code: OK (164.52=setup[121.12]+cmd[43.39] seconds)
  utilities-unittests: OK (70.51=setup[14.25]+cmd[56.16,0.10] seconds)
  congratulations :) (333.67 seconds)