fix: using a conditional check on a nowOnUpdate Date attribute

We need to remove the legacy logic for trying to ensure we always update
a Date with "nowOnUpdate" enabled. We now have a method on the table
called "updateOnSaveAttributes" that ensures properties that need to
self-check themselves do so, so this check is not necessary. By removing
this, it allows you to use a conditional check comparison (such as in a
transaction) against the date's previous value.

src/decorator/attribute-types/date.spec.ts

@@ -44,11 +44,13 @@ describe('AttributeType/Date', () => {
       await new Promise((resolve) => setTimeout(resolve, 2000))
 
       // save again
+      const updatedAtBeforeSave = record.updatedAt
       await record.save({ force: true }) // using force save so it saves, ignoring the fact there are no changes
 
       expect(record.updatedAt).to.be.a('date')
       expect(record.updatedAt).to.be.at.least(later)
       expect(record.updatedAt).to.be.at.within(later, new Date())
+      expect(record.updatedAt).to.not.eq(updatedAtBeforeSave)
 
       expect(record.getAttributeDynamoValue('createdAt')).to.deep.eq({
         S: record.createdAt.toISOString(),

src/decorator/attribute-types/date.ts

@@ -45,10 +45,6 @@ export class DateAttributeType extends AttributeType<Value, Metadata> implements
   }
 
   toDynamo(dt: Value): AttributeValue {
-    if (this.metadata?.nowOnUpdate === true) {
-      dt = new Date()
-    }
-
     if (this.metadata?.unixTimestamp === true || this.metadata?.millisecondTimestamp === true || this.metadata?.timeToLive === true) {
       return {
         N: this.parseDate(dt).toString(),
@@ -114,7 +110,7 @@ export class DateAttributeType extends AttributeType<Value, Metadata> implements
         // parse YYYY-MM-DD and ensure we create the Date object in UTC
         const b = dt.split('-').map((d) => parseInt(d, 10))
         dt = new Date(Date.UTC(b[0], --b[1], b[2]))
-      // if timestamp, assume the value is a timestamp
+      // if configured as a timestamp, assume the value is a numeric string as a timestamp
       } else if (this.metadata?.unixTimestamp === true || this.metadata?.timeToLive === true) {
         dt = new Date(stringToNumber(dt) * 1000)
       } else if (this.metadata?.millisecondTimestamp === true) {