### What changes were proposed in this pull request?
This patch proposes to add an internal config for ignoring metadata of `FileStreamSink` when reading the output path.
### Why are the changes needed?
`FileStreamSink` produces a metadata directory which logs output files per micro-batch. When we read from the output path, Spark will look at the metadata and ignore other files not in the log.
Normally it works well. But for some use-cases, we may need to ignore the metadata when reading the output path. For example, when we change the streaming query and must to run it with new checkpoint directory, we cannot use previous metadata. If we create a new metadata too, when we read the output path later in Spark, Spark only reads the files listed in the new metadata. The files written before we use new checkpoint and metadata are ignored by Spark.
Although seems we can output to different output directory every time, but it is bad idea as we will produce many directories unnecessarily.
We need a config for ignoring the metadata of `FileStreamSink` when reading the output path.
### Does this PR introduce _any_ user-facing change?
Added a config for ignoring metadata of FileStreamSink when reading the output.
### How was this patch tested?
Unit tests.
Closes#32702 from viirya/ignore-metadata.
Authored-by: Liang-Chi Hsieh <viirya@gmail.com>
Signed-off-by: Jungtaek Lim <kabhwan.opensource@gmail.com>
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