Speed up session initialization with lazy loading

[unixorn]

Only load the tab completions for op when we actually run op.

[github-actions[bot]]

🦙 MegaLinter status: ❌ ERROR

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ COPYPASTE	jscpd	yes		no	1.28s
✅ MARKDOWN	markdownlint	1		0	0.36s
✅ MARKDOWN	markdown-table-formatter	1		0	0.31s
❌ REPOSITORY	checkov	yes		2	14.34s
✅ REPOSITORY	devskim	yes		no	0.8s
✅ REPOSITORY	dustilock	yes		no	0.02s
✅ REPOSITORY	gitleaks	yes		no	0.14s
✅ REPOSITORY	git_diff	yes		no	0.04s
✅ REPOSITORY	secretlint	yes		no	2.13s
✅ REPOSITORY	syft	yes		no	0.27s
✅ REPOSITORY	trivy	yes		no	6.61s
✅ SPELL	misspell	1		0	0.09s

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