Panic on invalid input to `pdf::file::FileOptions::load`

## Describe the bug Panic could be triggered when passing `pdf::file::FileOptions::load` with invalid input. Panic info is shown below: ``` thread 'main' panicked at pdf/src/crypt.rs:156:18: range end index 16 out of range for slice of length 0 ``` Full stack backtrace: ```rust 0: rust_begin_unwind at /rustc/c987ad527540e8f1565f57c31204bde33f63df76/library/std/src/panicking.rs:652:5 1: core::panicking::panic_fmt at /rustc/c987ad527540e8f1565f57c31204bde33f63df76/library/core/src/panicking.rs:72:14 2: core::slice::index::slice_end_index_len_fail_rt at /rustc/c987ad527540e8f1565f57c31204bde33f63df76/library/core/src/slice/index.rs:66:5 3: core::slice::index::slice_end_index_len_fail at /rustc/c987ad527540e8f1565f57c31204bde33f63df76/library/core/src/slice/index.rs:59:5 4: <core::ops::range::Range<usize> as core::slice::index::SliceIndex<[T]>>::index at /rustc/c987ad527540e8f1565f57c31204bde33f63df76/library/core/src/slice/index.rs:405:13 5: <core::ops::range::RangeTo<usize> as core::slice::index::SliceIndex<[T]>>::index at /rustc/c987ad527540e8f1565f57c31204bde33f63df76/library/core/src/slice/index.rs:453:9 6: core::slice::index::<impl core::ops::index::Index<I> for [T]>::index at /rustc/c987ad527540e8f1565f57c31204bde33f63df76/library/core/src/slice/index.rs:18:9 7: <alloc::vec::Vec<T,A> as core::ops::index::Index<I>>::index at /rustc/c987ad527540e8f1565f57c31204bde33f63df76/library/alloc/src/vec/mod.rs:2907:9 8: pdf::crypt::Decoder::key at ./src/crypt.rs:156:18 9: pdf::crypt::Decoder::decrypt at ./src/crypt.rs:581:42 10: pdf::parser::Context::decrypt at ./src/parser/mod.rs:48:13 11: pdf::parser::_parse_with_lexer_ctx at ./src/parser/mod.rs:252:25 12: pdf::parser::parse_with_lexer_ctx at ./src/parser/mod.rs:132:11 13: pdf::parser::parse_dictionary_object at ./src/parser/mod.rs:81:26 14: pdf::parser::_parse_with_lexer_ctx at ./src/parser/mod.rs:151:23 15: pdf::parser::parse_with_lexer_ctx at ./src/parser/mod.rs:132:11 16: pdf::parser::parse_object::parse_indirect_object at ./src/parser/parse_object.rs:26:18 17: pdf::file::Storage<B,OC,SC,L>::resolve_ref at ./src/file.rs:248:32 18: <pdf::file::StorageResolver<B,OC,SC,L> as pdf::object::Resolve>::resolve_flags at ./src/file.rs:306:9 19: pdf::object::Resolve::resolve at ./src/object/mod.rs:63:9 20: <pdf::file::StorageResolver<B,OC,SC,L> as pdf::object::Resolve>::get::{{closure}} at ./src/file.rs:327:19 21: globalcache::sync::SyncCache<K,V>::get at /DATA2/dev/.cargo/registry/src/mirrors.ustc.edu.cn-61ef6e0cd06fb9b8/globalcache-0.2.4/src/sync.rs:71:29 22: <alloc::sync::Arc<globalcache::sync::SyncCache<pdf::object::PlainRef,T>> as pdf::file::Cache<T>>::get_or_compute at ./src/file.rs:55:9 23: <pdf::file::StorageResolver<B,OC,SC,L> as pdf::object::Resolve>::get at ./src/file.rs:326:19 24: <pdf::object::RcRef<T> as pdf::object::Object>::from_primitive at ./src/object/mod.rs:271:40 25: <core::option::Option<T> as pdf::object::Object>::from_primitive at ./src/object/mod.rs:741:24 26: <pdf::file::Trailer as pdf::object::FromDict>::from_dict at ./src/file.rs:672:10 27: <pdf::file::Trailer as pdf::object::Object>::from_primitive at ./src/file.rs:672:10 28: pdf::file::File<B,OC,SC,L>::load_data at ./src/file.rs:619:26 29: pdf::file::FileOptions<OC,SC,L>::load at ./src/file.rs:602:9 30: fz_unencrypted_strings::main at ./bin/fz_unencrypted_strings.rs:9:27 ``` ## Expected behavior Not panic. It could be an error reported to the users. ## Test environment: Version: pdf = main branch (commit: f87d3f5e90bddc9df8e0e144b06f2727e7afcc7e) OS: Ubuntu 20.04, 64 bit Target triple: x86_64-unknown-linux-gnu Rustc version: rustc 1.80.0-nightly (c987ad527 2024-05-01) ## To Reproduce It can be reproduced with the following program: ```rust fn main() { let p = "crash.pdf"; if let Ok(data) = std::fs::read(p) { if let Ok(file) = pdf::file::FileOptions::cached().load(data.as_slice()) { for idx in 0..file.num_pages() { let _ = file.get_page(idx); } } } } ``` crash.pdf is attached: [crash.pdf](https://github.com/user-attachments/files/20153426/crash.pdf)