BUG: Improve PdfWriter handing of context manager #5510

Job	Run time
Check code style issues	37s
pytest on windows	6m 54s
Build & verify package	13s
pytest on 3.8 (crypto-lib: cryptography)	2m 18s
pytest on 3.9 (crypto-lib: cryptography)	2m 12s
pytest on 3.10 (crypto-lib: cryptography)	5m 48s
pytest on 3.11 (crypto-lib: cryptography)	2m 31s
pytest on 3.12 (crypto-lib: cryptography)	2m 23s
pytest on 3.13 (crypto-lib: cryptography)	2m 20s
pytest on 3.8 (crypto-lib: pycryptodome)	2m 13s
pytest on 3.8 (crypto-lib: none)	2m 15s
Combine & check coverage.	0s
	29m 44s

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