feat(tmux): add `$ZSH_TMUX_SKIP_CONFIG`

[thanhnguyen2187]

Resolve #10367

Standards checklist:

• [x] The PR title is descriptive.
• [x] The PR doesn't replicate another PR which is already open.
• [x] I have read the contribution guide and followed all the instructions.
• [x] The code follows the code style guide detailed in the wiki.
• [x] The code is mine or it's from somewhere with an MIT-compatible license.
• [x] The code is efficient, to the best of my ability, and does not waste computer resources.
• [x] The code is stable and I have tested it myself, to the best of my abilities.

Changes:

• Add $ZSH_TMUX_SKIP_CONFIG to skip $ZSH_TMUX_CONFIG usage

Other comments:

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