chore(dynamodb): explicitly render false pointInTimeRecovery (#19757)

Today, if the property `pointInTimeRecoveryEnabled` is either `undefined`, or `false`,
we don't render the `pointInTimeRecoverySpecification` property in the Table L1.
A customer wants to write an Aspect that checks whether this property has been set,
and they cannot differentiate between the "not provided" and "set to `false`" cases.

Change the logic to render `pointInTimeRecoverySpecification` even for `false`
pointInTimeRecoveryEnabled values.

Fixes #19748

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packages/@aws-cdk/aws-dynamodb/lib/table.ts

@@ -1183,7 +1183,7 @@ export class Table extends TableBase {
       attributeDefinitions: this.attributeDefinitions,
       globalSecondaryIndexes: Lazy.any({ produce: () => this.globalSecondaryIndexes }, { omitEmptyArray: true }),
       localSecondaryIndexes: Lazy.any({ produce: () => this.localSecondaryIndexes }, { omitEmptyArray: true }),
-      pointInTimeRecoverySpecification: props.pointInTimeRecovery ? { pointInTimeRecoveryEnabled: props.pointInTimeRecovery } : undefined,
+      pointInTimeRecoverySpecification: props.pointInTimeRecovery != null ? { pointInTimeRecoveryEnabled: props.pointInTimeRecovery } : undefined,
       billingMode: this.billingMode === BillingMode.PAY_PER_REQUEST ? this.billingMode : undefined,
       provisionedThroughput: this.billingMode === BillingMode.PAY_PER_REQUEST ? undefined : {
         readCapacityUnits: props.readCapacity || 5,