refactor: remove duplicate combination code

Sources/TorusUtils/Extensions/TorusUtils+extension.swift

@@ -190,7 +190,7 @@ extension TorusUtils {
 
     private func reconstructKey(decryptedShares: [Int: String], thresholdPublicKey: KeyAssignment.PublicKey) throws -> String? {
         // run lagrange interpolation on all subsets, faster in the optimistic scenario than berlekamp-welch due to early exit
-        let allCombis = kCombinations(s: decryptedShares.count, k: 3)
+        let allCombis = combinations(elements: Array(0..<decryptedShares.count), k: 3)
         var returnedKey: String?
 
         for j in 0 ..< allCombis.count {

Sources/TorusUtils/Helpers/Common.swift

@@ -12,38 +12,3 @@ func generateAddressFromPubKey(publicKeyX: String, publicKeyY: String) -> String
     let ethAddrlower = "0x" + ethAddrData.toHexString()
     return ethAddrlower.toChecksumAddress()
 }
-
-func kCombinations(s: Any, k: Int) -> [[Int]] {
-    var set: [Int]
-    if let number = s as? Int {
-        set = Array(0 ..< number)
-    } else if let numbers = s as? [Int] {
-        set = numbers
-    } else {
-        return []
-    }
-
-    if k > set.count || k <= 0 {
-        return []
-    }
-
-    if k == set.count {
-        return [set]
-    }
-
-    if k == 1 {
-        return set.map { [$0] }
-    }
-
-    var combs: [[Int]] = []
-    var tailCombs: [[Int]] = []
-
-    for i in 0 ... set.count - k {
-        tailCombs = kCombinations(s: Array(set[(i + 1)...]), k: k - 1)
-        for j in 0 ..< tailCombs.count {
-            combs.append([set[i]] + tailCombs[j])
-        }
-    }
-
-    return combs
-}