update instances of Collection.getIDs().length with .getLength()

contracts/NonFungibleToken-v2.cdc

@@ -247,7 +247,7 @@ access(all) contract NonFungibleToken {
         /// and returns it to the caller so that they can own NFTs
         access(all) fun createEmptyCollection(): @{Collection} {
             post {
-                result.getIDs().length == 0: "The created collection must be empty!"
+                result.getLength() == 0: "The created collection must be empty!"
             }
         }
 

scripts/get_collection_length.cdc

@@ -12,5 +12,5 @@ access(all) fun main(address: Address): Int {
             collectionData.publicPath
         ) ?? panic("Could not borrow capability from public collection")
 
-    return collectionRef.getIDs().length
+    return collectionRef.getLength()
 }

scripts/get_collection_length_from_storage.cdc

@@ -12,5 +12,5 @@ access(all) fun main(address: Address): Int {
             from: collectionData.storagePath
         ) ?? panic("Could not borrow reference to collection from storage")
 
-    return collectionRef.getIDs().length
+    return collectionRef.getLength()
 }

tests/scripts/get_nft_metadata.cdc

@@ -181,7 +181,7 @@ access(all) fun main(address: Address, id: UInt64): Bool {
     assert(nil == nftMetadata.license)
 
     let coll <- nftCollectionView.createEmptyCollection()
-    assert(0 == coll.getIDs().length)
+    assert(0 == coll.getLength())
     destroy <- coll
 
     return true

tests/scripts/resolve_nft_views.cdc

@@ -34,7 +34,7 @@ access(all) fun main(): Bool {
     assert(Type<auth(NonFungibleToken.Withdrawable) &ExampleNFT.Collection>() == collectionData.providerLinkedType)
 
     let coll <- collectionData.createEmptyCollection()
-    assert(0 == coll.getIDs().length)
+    assert(0 == coll.getLength())
 
     destroy <- coll