fix: add URL encoding to EmbeddedChatApi request parameters

[sudorishabh]

Brief Title

This PR fixes a bug where special characters (like &, #, or spaces) in search terms, room IDs, or usernames would break API requests because they weren't being URL-encoded.

Why needed?

Without encoding, a search for "Test & Fix" would result in a URL like .../chat.search?searchText=Test & Fix. The server sees the & and stops reading the search text, causing incomplete or failed results.

Fixes #1192

Affected Methods:

• getSearchMessages (searchText, roomId)
• getMessages / getOlderMessages (query, field, roomId)
• getUsersInRole (role)
• userData / userInfo (username, userId)
• getThreadMessages (tmid)
• getAllFiles (typeGroup, roomId)
• Various other methods using this.rid in GET URLs (e.g., rooms.info, rooms.images, members).

// Before
`${this.host}/api/v1/chat.search?roomId=${this.rid}&searchText=${text}`

// After
`${this.host}/api/v1/chat.search?roomId=${encodeURIComponent(this.rid)}&searchText=${encodeURIComponent(text)}`

PR Test Details

Note: The PR will be ready for live testing at https://rocketchat.github.io/EmbeddedChat/pulls/pr-1192 after approval.