Revert "use Int32 instead UInt32 as index type in (sparse) projections"

Indeed, it seems that we are actually hitting the typemax(Int32)
boundary in some cases and UInt32 is necessary here

This reverts commit ba9af48.

src/matrix_projections.jl

@@ -174,8 +174,8 @@ function matrix_projection_irr_acc!(
     weight,
 )
     iszero(weight) && return result
-    I = Int32[]
-    J = Int32[]
+    I = UInt32[]
+    J = UInt32[]
     V = eltype(result)[]
     for (val, cc) in zip(vals, ccls)
         iszero(val) && continue
@@ -232,8 +232,8 @@ function matrix_projection_irr_acc!(
     weight,
 )
     iszero(weight) && return result
-    I = Int32[]
-    J = Int32[]
+    I = UInt32[]
+    J = UInt32[]
     V = eltype(result)[]
     for (val, ccl) in zip(class_values, conjugacy_cls)
         iszero(val) && continue
@@ -304,8 +304,8 @@ function matrix_representation_acc!(
     },
 )
     b = basis(parent(α))
-    I = Int32[]
-    J = Int32[]
+    I = UInt32[]
+    J = UInt32[]
     V = eltype(result)[]
     for (idx, val) in StarAlgebras._nzpairs(StarAlgebras.coeffs(α))
         g = b[idx]
@@ -326,8 +326,8 @@ function matrix_representation_acc!(
     α::AlgebraElement,
 )
     b = basis(parent(α))
-    I = Int32[]
-    J = Int32[]
+    I = UInt32[]
+    J = UInt32[]
     V = eltype(result)[]
     for (idx, val) in StarAlgebras._nzpairs(StarAlgebras.coeffs(α))
         iszero(val) && continue