Set properties boolean value to lowercase string

[kevinjqliu]

Apache Iceberg version

None

Please describe the bug 🐞

Issue

As shown in #895, setting a property to python's boolean value (True/False) will end up saving the boolean value as the string value "True"/"False". This is because the property dictionary's values are converted to string by transform_dict_value_to_str implemented in #504.
So True -> "True"

Fix

I can see this as a common footgun. Let's add a fix so that any boolean in the properties dictionary values are converted to its lowercase string.

Example

As a concrete example:

catalog.create_table(
    "default.example",
    schema=Schema(
        NestedField(1, "created_at", TimestampType(), required=True)
    ),
    properties={"write.parquet.bloom-filter-enabled.column.material_id": True},
)

Will set the property as

{"write.parquet.bloom-filter-enabled.column.material_id": "True"}

But the expected value should be

{"write.parquet.bloom-filter-enabled.column.material_id": "true"}

[soumya-ghosh]

@kevinjqliu could I pick this up?

[Fokko]

@soumya-ghosh assigned it to you 👍

[soumya-ghosh]

@Fokko @kevinjqliu PR #924 is ready for review.

[kevinjqliu]

Resolved in #924