Base: Removed unused private variable decimals to avoid lint issue.

The linter report 'private field 'decimals' is not used'.  The
getDecimals() method return pack.defDecimals, which was also
used to set the value of the decimals variable in the initializer,
so the decimals variable is redundant.

src/Base/UnitsSchemas.cpp

@@ -44,7 +44,6 @@ using Base::UnitsSchemaSpec;
 UnitsSchemas::UnitsSchemas(const UnitsSchemasDataPack& pack)
     : pack {pack}
     , denominator {pack.defDenominator}
-    , decimals {pack.defDecimals}
 {}
 
 size_t UnitsSchemas::count() const

src/Base/UnitsSchemas.h

@@ -71,7 +71,6 @@ private:
     UnitsSchemasDataPack pack;
     std::unique_ptr<UnitsSchema> current {std::make_unique<UnitsSchema>(spec())};
     std::size_t denominator;
-    std::size_t decimals;
 };