Add support for importing aws_dynamodb_table_item

[icholy]

Description

Add support for importing aws_dynamodb_table_item. The import id format is the same as the resource id: tableName|hashKeyName|hashKeyValue[|rangeKeyValue]. This has the unfortunate limitation of not allowing | to be used in the key value.

Output from Acceptance Testing

% AWS_PROFILE=default make testacc TESTS=TestAccDynamoDBTableItem PKG=dynamodb
make: Verifying source code with gofmt...
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go1.24.6 test ./internal/service/dynamodb/... -v -count 1 -parallel 20 -run='TestAccDynamoDBTableItem'  -timeout 360m -vet=off
2025/09/02 13:17:12 Creating Terraform AWS Provider (SDKv2-style)...
2025/09/02 13:17:12 Initializing Terraform AWS Provider (SDKv2-style)...
=== RUN   TestAccDynamoDBTableItemDataSource_basic
=== PAUSE TestAccDynamoDBTableItemDataSource_basic
=== RUN   TestAccDynamoDBTableItemDataSource_projectionExpression
=== PAUSE TestAccDynamoDBTableItemDataSource_projectionExpression
=== RUN   TestAccDynamoDBTableItemDataSource_expressionAttributeNames
=== PAUSE TestAccDynamoDBTableItemDataSource_expressionAttributeNames
=== RUN   TestAccDynamoDBTableItem_basic
=== PAUSE TestAccDynamoDBTableItem_basic
=== RUN   TestAccDynamoDBTableItem_rangeKey
=== PAUSE TestAccDynamoDBTableItem_rangeKey
=== RUN   TestAccDynamoDBTableItem_withMultipleItems
=== PAUSE TestAccDynamoDBTableItem_withMultipleItems
=== RUN   TestAccDynamoDBTableItem_withDuplicateItemsSameRangeKey
=== PAUSE TestAccDynamoDBTableItem_withDuplicateItemsSameRangeKey
=== RUN   TestAccDynamoDBTableItem_withDuplicateItemsDifferentRangeKey
=== PAUSE TestAccDynamoDBTableItem_withDuplicateItemsDifferentRangeKey
=== RUN   TestAccDynamoDBTableItem_wonkyItems
=== PAUSE TestAccDynamoDBTableItem_wonkyItems
=== RUN   TestAccDynamoDBTableItem_update
=== PAUSE TestAccDynamoDBTableItem_update
=== RUN   TestAccDynamoDBTableItem_updateWithRangeKey
=== PAUSE TestAccDynamoDBTableItem_updateWithRangeKey
=== RUN   TestAccDynamoDBTableItem_disappears
=== PAUSE TestAccDynamoDBTableItem_disappears
=== RUN   TestAccDynamoDBTableItem_mapOutOfBandUpdate
=== PAUSE TestAccDynamoDBTableItem_mapOutOfBandUpdate
=== CONT  TestAccDynamoDBTableItemDataSource_basic
=== CONT  TestAccDynamoDBTableItem_withDuplicateItemsDifferentRangeKey
=== CONT  TestAccDynamoDBTableItem_rangeKey
=== CONT  TestAccDynamoDBTableItem_withDuplicateItemsSameRangeKey
=== CONT  TestAccDynamoDBTableItem_withMultipleItems
=== CONT  TestAccDynamoDBTableItemDataSource_projectionExpression
=== CONT  TestAccDynamoDBTableItem_updateWithRangeKey
=== CONT  TestAccDynamoDBTableItem_disappears
=== CONT  TestAccDynamoDBTableItem_mapOutOfBandUpdate
=== CONT  TestAccDynamoDBTableItem_update
=== CONT  TestAccDynamoDBTableItem_wonkyItems
=== CONT  TestAccDynamoDBTableItemDataSource_expressionAttributeNames
=== CONT  TestAccDynamoDBTableItem_basic
--- PASS: TestAccDynamoDBTableItem_withDuplicateItemsSameRangeKey (20.34s)
--- PASS: TestAccDynamoDBTableItemDataSource_expressionAttributeNames (29.96s)
--- PASS: TestAccDynamoDBTableItemDataSource_basic (30.01s)
--- PASS: TestAccDynamoDBTableItem_withDuplicateItemsDifferentRangeKey (30.26s)
--- PASS: TestAccDynamoDBTableItem_withMultipleItems (31.89s)
--- PASS: TestAccDynamoDBTableItem_disappears (32.07s)
--- PASS: TestAccDynamoDBTableItem_basic (33.70s)
--- PASS: TestAccDynamoDBTableItem_rangeKey (33.74s)
--- PASS: TestAccDynamoDBTableItem_wonkyItems (37.17s)
--- PASS: TestAccDynamoDBTableItemDataSource_projectionExpression (37.25s)
--- PASS: TestAccDynamoDBTableItem_mapOutOfBandUpdate (40.82s)
--- PASS: TestAccDynamoDBTableItem_update (43.35s)
--- PASS: TestAccDynamoDBTableItem_updateWithRangeKey (49.60s)
PASS
ok  	github.com/hashicorp/terraform-provider-aws/internal/service/dynamodb	49.778s

[github-actions]

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[github-actions]

✅ Thank you for correcting the previously detected issues! The maintainers appreciate your efforts to make the review process as smooth as possible.