fix(xo-server/xapi): don't silently swallow errors on _callInstallationPlugin (#5809)
fix(xo-server/xapi): don't silently swallow errors on _callInstallationPlugin (#5809)

See xoa-support#3738

Introduced by a73acedc4d8c47d9772488e6615eb1d4ec8c4417

This was done to prevent triggering an error when the pack was already
installed but a XENAPI_PLUGIN_FAILURE error can happen for other reasons
vatesfr/xo-web,lmcro/xo-web,lmcro/xo-web,vatesfr/xo-web,lmcro/xo-web