feat(ipc): add with_skip_validation to StreamDecoder (#9749)

# Which issue does this PR close?

N/A - this is a small API parity fix.

# Rationale for this change

`StreamReader` and `FileDecoder` both expose `with_skip_validation` but
`StreamDecoder` does not, despite having the same internal
`skip_validation` field.
Motivation: DataFusion's spill infrastructure is being refactored to use
`StreamDecoder` for reading spill files via a pluggable backend trait
([apache/datafusion#21215](apache/datafusion#21215)).
Since DataFusion controls what it writes it can trust its own IPC
output, and needs this method to maintain the same performance
characteristic as the current StreamReader-based implementation

# What changes are included in this PR?

Adds `with_skip_validation` to `StreamDecoder` mirroring the existing
implementation on `FileDecoder`

# Are these changes tested?

The existing StreamDecoder tests cover the decoding path. No new tests
added as this method sets an internal flag already tested via
`FileDecoder` and `StreamReader`.

# Are there any user-facing changes?

Yes, `with_skip_validation` is now available on `StreamDecoder`. It is
marked unsafe with the same safety requirements as
`FileDecoder::with_skip_validation`.

Author: pantShrey

arrow-ipc/src/reader/stream.rs

@@ -45,9 +45,8 @@ pub struct StreamDecoder {
     require_alignment: bool,
     /// Should validation be skipped when reading data? Defaults to false.
     ///
-    /// See [`FileDecoder::with_skip_validation`] for details.
+    /// See [`StreamDecoder::with_skip_validation`] for details.
     ///
-    /// [`FileDecoder::with_skip_validation`]: crate::reader::FileDecoder::with_skip_validation
     skip_validation: UnsafeFlag,
 }
 
@@ -114,6 +113,20 @@ impl StreamDecoder {
         self.schema.as_ref().map(|schema| schema.clone())
     }
 
+    /// Specifies if validation should be skipped when reading data (defaults to `false`)
+    ///
+    /// # Safety
+    ///
+    /// This flag must only be set to `true` when you trust the input data and are
+    /// sure the data you are reading is valid Arrow IPC stream data, otherwise
+    /// undefined behavior may result.
+    ///
+    /// For example, DataFusion uses this when reading spill files it wrote itself.
+    pub unsafe fn with_skip_validation(mut self, skip_validation: bool) -> Self {
+        unsafe { self.skip_validation.set(skip_validation) };
+        self
+    }
+
     /// Try to read the next [`RecordBatch`] from the provided [`Buffer`]
     ///
     /// [`Buffer::advance`] will be called on `buffer` for any consumed bytes.