Fix potential infinite loop when calculating tile editor zoom level #19008

Job	Run time
📊 Static checks / Code style, file formatting, and docs	1m 3s
🍏 iOS / Template (target=template_release)	2m 38s
🐧 Linux / Editor w/ Mono (target=editor)	35m 35s
🍎 macOS / Editor (target=editor, tests=yes)	4m 1s
🐧 Linux / Editor with doubles and GCC sanitizers (target=editor, tests=yes, dev_build=yes, scu_build=yes, precision=double, use_asan=yes, use_ubsan=yes, linker=gold)	36m 27s
🌐 Web / Template (target=template_release)	20m 11s
🍎 macOS / Template (target=template_release)	3m 6s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	30m 30s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	27m 43s
🐧 Linux / Template w/ Mono (target=template_release)	23m 53s
🤖 Android / Template (target=template_release)	27m 53s
🏁 Windows / Editor (target=editor, tests=yes)	41m 22s
🏁 Windows / Template (target=template_release)	30m 39s
🐧 Linux / Minimal template (target=template_release, everything disabled)	14m 24s
🪲 Godot CPP / Build and test Godot CPP	6m 44s
	5h 6m 9s

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