Better handle string argument functions #7676

Job	Run time
LPython CI (3.10, windows-2025)	19m 57s
LPython CI (3.10, ubuntu-latest)	10m 38s
Build LPython to WASM	7m 5s
LPython CI (3.10, macos-latest)	8m 48s
Test PIP Installable Packages	3m 9s
Run SymPy tests	4m 18s
Run Integration tests with Python 3.12	4m 10s
Run Integration tests with Python 3.9	4m 9s
Run Integration tests with Python 3.10	4m 31s
Test CPython Interop (@pythoncall)	2m 59s
Test LLVM 16	3m 29s
Test LLVM 15	3m 22s
Build Jupyter Kernel	3m 58s
Run Integration tests with Python 3.11	4m 41s
Test LLVM 10	3m 30s
Check Release build	8m 15s
Check Debug build	3m 26s
Upload Tarball	52s
	1h 41m 17s

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