refactor: eliminating indexing_slicing #17005

Job	Run time
cargo deny	33s
Build C library (ubuntu-latest)	2m 37s
Rust doc comments	24s
Build C library (macos-latest)	2m 9s
Lint Rust	2m 37s
Check if node constants are up to date	5s
Check provider database	4s
Rust tests (ubuntu-latest, 1.82.0)	4m 33s
Rust tests (windows-latest, 1.82.0)	15m 30s
Python lint	13s
Build deltachat-rpc-server (ubuntu-latest)	2m 8s
Rust tests (macos-latest, 1.82.0)	3m 19s
Build deltachat-rpc-server (macos-latest)	2m 26s
Rust tests (ubuntu-latest, 1.77.0)	3m 27s
Build deltachat-rpc-server (windows-latest)	13m 1s
CFFI Python tests (ubuntu-latest, 3.13)	6m 1s
CFFI Python tests (macos-latest, 3.13)	6m 16s
CFFI Python tests (ubuntu-latest, pypy3.10)	6m 28s
CFFI Python tests (macos-latest, pypy3.10)	6m 31s
CFFI Python tests (ubuntu-latest, 3.7)	7m 11s
JSON-RPC Python tests (ubuntu-latest, 3.13)	2m 27s
JSON-RPC Python tests (macos-latest, 3.13)	2m 26s
JSON-RPC Python tests (windows-latest, 3.13)	3m 14s
JSON-RPC Python tests (ubuntu-latest, pypy3.10)	2m 23s
JSON-RPC Python tests (macos-latest, pypy3.10)	2m 50s
JSON-RPC Python tests (ubuntu-latest, 3.7)	2m 39s
	1h 41m 32s

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