Update Rust crate indexmap to v2.9.0

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
indexmap	dependencies	minor	=2.8.0 -> =2.9.0

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Release Notes

indexmap-rs/indexmap (indexmap)

v2.9.0

Compare Source

• Added a get_disjoint_mut method to IndexMap, matching Rust 1.86's
  HashMap method.
• Added a get_disjoint_indices_mut method to IndexMap and map::Slice,
  matching Rust 1.86's get_disjoint_mut method on slices.
• Deprecated the borsh feature in favor of their own indexmap feature,
  solving a cyclic dependency that occured via borsh-derive.

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