[MINOR][DOCS] Fix the Binder link to point the quickstart notebook correctly

### What changes were proposed in this pull request?

This PR fixes the link of Binder in Quickstart notebook and documentation.

From:

https://mybinder.org/v2/gh/databricks/apache/master?filepath=python%2Fdocs%2Fsource%2Fgetting_started%2Fquickstart.ipynb

To:

https://mybinder.org/v2/gh/apache/spark/master?filepath=python%2Fdocs%2Fsource%2Fgetting_started%2Fquickstart.ipynb

This link is the same as the one in RST files:

https://github.com/apache/spark/blob/b54103016a01d77f074295db82f96087f45cef4f/python/docs/source/conf.py#L57

### Why are the changes needed?

The link was wrong, and points out non-existent file and repo.

### Does this PR introduce _any_ user-facing change?

Yes, it will fixes the link so users can correctly try Binder.

### How was this patch tested?

Manually tested by building the documentation.

Closes #29597 from HyukjinKwon/minor-link-quickstart.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>

Author: HyukjinKwon

python/docs/source/getting_started/quickstart.ipynb

@@ -7,7 +7,7 @@
     "# Quickstart\n",
     "\n",
     "This is a short introduction and quickstart for the PySpark DataFrame API. PySpark DataFrames are lazily evaluated. They are implemented on top of [RDD](https://spark.apache.org/docs/latest/rdd-programming-guide.html#overview)s. When Spark [transforms](https://spark.apache.org/docs/latest/rdd-programming-guide.html#transformations) data, it does not immediately compute the transformation but plans how to compute later. When [actions](https://spark.apache.org/docs/latest/rdd-programming-guide.html#actions) such as `collect()` are explicitly called, the computation starts.\n",
-    "This notebook shows the basic usages of the DataFrame, geared mainly for new users. You can run the latest version of these examples by yourself on a live notebook [here](https://mybinder.org/v2/gh/databricks/apache/master?filepath=python%2Fdocs%2Fsource%2Fgetting_started%2Fquickstart.ipynb).\n",
+    "This notebook shows the basic usages of the DataFrame, geared mainly for new users. You can run the latest version of these examples by yourself on a live notebook [here](https://mybinder.org/v2/gh/apache/spark/master?filepath=python%2Fdocs%2Fsource%2Fgetting_started%2Fquickstart.ipynb).\n",
     "\n",
     "There is also other useful information in Apache Spark documentation site, see the latest version of [Spark SQL and DataFrames](https://spark.apache.org/docs/latest/sql-programming-guide.html), [RDD Programming Guide](https://spark.apache.org/docs/latest/rdd-programming-guide.html), [Structured Streaming Programming Guide](https://spark.apache.org/docs/latest/structured-streaming-programming-guide.html), [Spark Streaming Programming Guide](https://spark.apache.org/docs/latest/streaming-programming-guide.html) and [Machine Learning Library (MLlib) Guide](https://spark.apache.org/docs/latest/ml-guide.html).\n",
     "\n",