Revise and clean up some icons (#35582)

This is really just a small beginning, as there are many other icons to
be revised and cleaned up. Our current set is a bit of a mess in terms
of dimension, spacing, stroke width, and terminology. I'm sure there are
more non-used icons I'm not covering here, too. We'll hopefully tackle
it all soon leading up to 1.0.

Closes https://github.com/zed-industries/zed/issues/35576

Release Notes:

- N/A

crates/language_models/src/provider/lmstudio.rs

@@ -744,7 +744,7 @@ impl Render for ConfigurationView {
                                     Button::new("retry_lmstudio_models", "Connect")
                                         .icon_position(IconPosition::Start)
                                         .icon_size(IconSize::XSmall)
-                                        .icon(IconName::Play)
+                                        .icon(IconName::PlayOutlined)
                                         .on_click(cx.listener(move |this, _, _window, cx| {
                                             this.retry_connection(cx)
                                         })),

crates/language_models/src/provider/ollama.rs

@@ -658,7 +658,7 @@ impl Render for ConfigurationView {
                                     Button::new("retry_ollama_models", "Connect")
                                         .icon_position(IconPosition::Start)
                                         .icon_size(IconSize::XSmall)
-                                        .icon(IconName::Play)
+                                        .icon(IconName::PlayOutlined)
                                         .on_click(cx.listener(move |this, _, _, cx| {
                                             this.retry_connection(cx)
                                         })),