fix: window. rainbow providers

[estebanmino]

Fixes BX-#### Figma link (if any):

What changed (plus any additional context for devs)

window.rainbow.providers was only defined once at the beginning, so any updates to rnbwWalletRouter.providers won't be reflected in window.rainbow.providers, in which case were rainbow provider is window.ethereum the window.ethereum.providers would only have the first definition of window.rainbow.providers at the beginning

EDIT

ended up removing isMetaMask flag when announceProvider

Screen recordings / screenshots

What to test

[magiziz]

When testing with manifold and 1inch it seems like giving me these errors:

[github-actions[bot]]

Here's the packed extension for this build: node_modules.tar.gz rainbowbx-4ec33ee1425e23d2c4f301e0bd0402f813573a19 screenshots

[github-actions[bot]]

Here's the packed extension for this build: node_modules.tar.gz rainbowbx-8072ba6425772907a0d775f132880b3a7615ab1d screenshots

[github-actions[bot]]

Here's the packed extension for this build: rainbowbx-b11a2caa92d13aff11cce8f2ed142adfb92405f8

[github-actions[bot]]

Here's the packed extension for this build: node_modules.tar.gz rainbowbx-4d6baad50ce738e08e9dcadca5a2aa98120dd437