[Infra UI] Consistency in the popover styling (#166189)

Closes #165960 
## Summary

This PR sets all popups inside host view padding to size s (8px)

### Testing

- Open the host view and check the popup size (should be 8px - size s):
<img width="1303" alt="image"
src="https://github.com/elastic/kibana/assets/14139027/b3242de6-5644-4a1d-9f10-7b9a76269848">

- Open metadata and processes message popups - they should have the same
padding size:
   - Metadata Tab
   
<img width="1002" alt="image"
src="https://github.com/elastic/kibana/assets/14139027/e1c157aa-ced6-4a2e-9458-a38b99328276">

   - Overview Tab
   
<img width="585" alt="image"
src="https://github.com/elastic/kibana/assets/14139027/878c1325-28af-4b16-9ec4-93a0fc620c87">

   - Processes Tab
   
<img width="1147" alt="image"
src="https://github.com/elastic/kibana/assets/14139027/70dfc49f-ef1a-4786-bab4-7a3715af7f85">

x-pack/plugins/infra/public/components/asset_details/components/metadata_explanation.tsx

@@ -21,7 +21,7 @@ const MetadataExplanationTooltipContent = React.memo(() => {
   };
 
   return (
-    <EuiText size="s" onClick={onClick} style={{ width: 200 }}>
+    <EuiText size="xs" onClick={onClick} style={{ width: 200 }}>
       <FormattedMessage
         id="xpack.infra.assetDetails.metadata.tooltip.documentationLabel"
         defaultMessage="{metadata} is populated from the last event detected for this {hostName} for the selected date period."
@@ -91,7 +91,6 @@ export const MetadataExplanationMessage = () => {
           iconSize="s"
           iconColor="subdued"
           icon="iInCircle"
-          panelPaddingSize="m"
           data-test-subj="infraAssetDetailsMetadataPopoverButton"
         >
           <MetadataExplanationTooltipContent />

x-pack/plugins/infra/public/components/asset_details/components/processes_explanation.tsx

@@ -22,7 +22,7 @@ const ProcessesExplanationTooltipContent = React.memo(() => {
   };
 
   return (
-    <EuiText size="s" onClick={onClick} style={{ width: 300 }}>
+    <EuiText size="xs" onClick={onClick} style={{ width: 300 }}>
       <p>
         <FormattedMessage
           id="xpack.infra.assetDetails.processes.tooltip.explanationLabel"
@@ -100,7 +100,6 @@ export const ProcessesExplanationMessage = () => {
           iconSize="s"
           iconColor="subdued"
           icon="iInCircle"
-          panelPaddingSize="m"
           data-test-subj="infraAssetDetailsProcessesPopoverButton"
         >
           <ProcessesExplanationTooltipContent />

x-pack/plugins/infra/public/components/asset_details/tabs/common/popover.tsx

@@ -5,7 +5,6 @@
  * 2.0.
  */
 
-import { PanelPaddingSize } from '@elastic/eui';
 import { EuiPopover, EuiIcon, type IconType, type IconColor, type IconSize } from '@elastic/eui';
 import { css } from '@emotion/react';
 import React from 'react';
@@ -16,20 +15,18 @@ export const Popover = ({
   icon,
   iconColor,
   iconSize,
-  panelPaddingSize,
   ...props
 }: {
   children: React.ReactNode;
   icon: IconType;
   iconColor?: IconColor;
   iconSize?: IconSize;
-  panelPaddingSize?: PanelPaddingSize;
   'data-test-subj'?: string;
 }) => {
   const [isPopoverOpen, { off: closePopover, toggle: togglePopover }] = useBoolean(false);
   return (
     <EuiPopover
-      panelPaddingSize={panelPaddingSize ?? 's'}
+      panelPaddingSize="s"
       button={
         <EuiIcon
           data-test-subj={props['data-test-subj']}