ExtractROI should make "mode.fit.im" and "mode.fit.ref" as optional parameters

Description

Cannot run otb::ExtractROI in qgis. An error says 'mode.fit.im' value is None, even when 'mode' parameter is set to 'standard'. This is because these parameters are marked mandatory in descriptor files.

See below output from ./bin/otbcli_ExtractROI -help

Parameters:
MISSING -in                <string>         Input Image  (mandatory)
MISSING -out               <string> [pixel] Output Image  [pixel=uint8/uint16/int16/uint32/int32/float/double/cint16/cint32/cfloat/cdouble] (default value is float) (mandatory)
        -mode              <string>         Extraction mode [standard/fit/extent/radius] (mandatory, default value is standard)
        -mode.fit.im       <string>         Reference image  (mandatory)
        -mode.fit.vect     <string>         Reference vector  (mandatory)
        -mode.extent.ulx   <float>          X coordinate of the Upper left corner  (mandatory, default value is 0)
        -mode.extent.uly   <float>          Y coordinate of Upper Left corner point  (mandatory, default value is 0)
        -mode.extent.lrx   <float>          X coordinate of Lower Right corner point  (mandatory, default value is 0)
        -mode.extent.lry   <float>          Y coordinate of Lower Right corner point  (mandatory, default value is 0)
        -mode.extent.unit  <string>         Unit [pxl/phy/lonlat] (mandatory, default value is pxl)
        -mode.radius.r     <float>          Radius  (mandatory, default value is 0)
        -mode.radius.unitr <string>         Radius unit [pxl/phy] (mandatory, default value is pxl)
        -mode.radius.cx    <float>          X coordinate of the center  (mandatory, default value is 0)
        -mode.radius.cy    <float>          Y coordinate of the center  (mandatory, default value is 0)
        -mode.radius.unitc <string>         Center unit [pxl/phy/lonlat] (mandatory, default value is pxl)
        -startx            <int32>          Start X  (mandatory, default value is 0)
        -starty            <int32>          Start Y  (mandatory, default value is 0)
        -sizex             <int32>          Size X  (mandatory, default value is 0)
        -sizey             <int32>          Size Y  (mandatory, default value is 0)
        -cl                <string list>    Output Image channels  (mandatory, no default value)
        -elev              <group>          Elevation management
        -elev.dem          <string>         DEM directory  (optional, off by default)
        -elev.geoid        <string>         Geoid File  (optional, off by default)
        -elev.default      <float>          Default elevation  (mandatory, default value is 0)
        -ram               <int32>          Available RAM (MB)  (optional, off by default, default value is 128)
        -inxml             <string>         Load parameters from XML  (optional, off by default)
        -progress          <boolean>        Report progress
        -help              <string list>    Display long help (empty list), or help for given parameters keys

"mode.fit.*" parameters shouldn't be bothered when value of 'mode' parameter is set to 'standard'. The sub-parameters of "mode.fit" are not optional and cause failure in qgis. Running this app on command line is working.

But QGIS requires (and is right) all mandatory parameters must be set. Parameters (like above) that depend on value of another parameter must be marked optional.

Steps to reproduce

Run otb::ExtractROI with qgis

Configuration information

OS, OTB version or tag, information related to build (binaries, superbuild, system libs ...)