[BIP-646] Enable instETH-wstETH Gauge Arbitrum

[Zen-Maxi]

Enable Gauge on Arbitrum for instETH/wstETH.
Rate provider review: balancer/code-review#91 Proposal: https://forum.balancer.fi/t/bip-xxx-enable-gauge-for-insteth-wsteth-arbitrum/5834

[github-actions]

BIP validation results for file BIPs/2024-W27/[BIP-646] Enable instETH-wstETH Gauge Arbitrum.json:
Commit: 80cbc845595f9513d1cd1c55a67b065fe6991b36

Validator	Result
validate_contains_msig	OK
validate_msig_in_address_book	OK
validate_chain_specified	OK
validate_file_has_bip	OK
validate_path_has_weekly_dir	OK

[github-actions]

FILENAME: BIPs/2024-W27/[BIP-646] Enable instETH-wstETH Gauge Arbitrum.json
MULTISIG: multisigs/lm (mainnet:0xc38c5f97B34E175FFd35407fc91a937300E33860)
COMMIT: 80cbc845595f9513d1cd1c55a67b065fe6991b36
CHAIN(S): arbitrum
TENDERLY: SUCCESS

+-----------------------+---------------------------------------------------------------------+-----------------+--------------------------------------------+------------------------------------------------------------+--------------------------------------------+----------------+---------+----------+
| function              | pool_id_and_address                                                 | symbol_and_info | gauge_address_and_info                     | tokens                                                     | rate_providers                             | review_summary |   bip   | tx_index |
+-----------------------+---------------------------------------------------------------------+-----------------+--------------------------------------------+------------------------------------------------------------+--------------------------------------------+----------------+---------+----------+
| GaugeAdderV4/addGauge | 0x5b89dc91e5a4dc6d4ab0d970af6a7f981971a443000000000000000000000572  | instETH/wstETH  | 0x82bc385C57447188de50Ba8237210cAaA43a0BB3 | 0x5979D7b546E38E414F7E9822514be443A4800529: wstETH         | 0xf7c5c26B574063e7b098ed74fAd6779e65E3F836 |      safe      | BIP-646 |    0     |
|                       | pool_address: 0x5b89dC91E5a4Dc6D4AB0D970AF6A7F981971a443            | fee: 0.04       | Style: L0 sidechain                        | 0x5b89dC91E5a4Dc6D4AB0D970AF6A7F981971a443: instETH/wstETH | 0x0000000000000000000000000000000000000000 |       --       |         |          |
|                       |                                                                     | a-factor: 200   | cap: 100.0%                                | 0xd08C3F25862077056cb1b710937576Af899a4959: InstETH        | 0x57a5a0567187FF4A8dcC1A9bBa86155E355878F2 | !!NO REVIEW!!  |         |          |
+-----------------------+---------------------------------------------------------------------+-----------------+--------------------------------------------+------------------------------------------------------------+--------------------------------------------+----------------+---------+----------+

[gosuto-inzasheru]

rate provider report still waiting for peer review